Products / Thermax

Thermax temperature indicator strips

Thermax industrial temperature indicators: self-adhesive, irreversible temperature indicator strips — also known as irreversible temperature labels or self-adhesive thermometers — provide a permanent record of surface temperature. When a temperature threshold is exceeded, the corresponding indicator area changes from transparent to black.

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Applications and selection

Irreversible maximum temperature indicator 25–300 °C

Thermax temperature indicator strips are used for process monitoring, testing and measurement where a permanent record that a temperature has been reached is required. Applications include engines, bearings, transformers, machine components, automotive and aerospace manufacturing, quality control, maintenance, and processes involving food and medical equipment.

When a temperature threshold is exceeded, the corresponding field turns permanently black. The strip requires no battery or activation and can be peeled off after measurement and attached to a report. Versions with one to eleven fields allow users to check a single threshold or estimate the maximum temperature reached more precisely.

Machinery manufacturers use irreversible temperature labels as thermal seals: a strip on an engine, pump or gearbox provides permanent evidence of overheating when assessing a warranty claim.

Technical information

Irreversible self-adhesive temperature indicators

Each indicator consists of temperature-sensitive elements protected by heat-resistant layers with transparent windows. It responds immediately, and the reading remains visible even after cooling. The label can be peeled off and attached to an inspection report.

Clear change from transparent to black in the indicator window

Ready to use — no prior activation required

Immediate, irreversible response to temperature

Resistant to oil, water and water vapour

Accuracy tolerance

Indication accuracy

25–99 °C±1 °C

100–154 °C±1.5 °C

160–300 °C±1% + 1 °C

Store in a cool, dry place at a temperature below the indicator's lowest threshold temperature.

Available variants

Thermax strip variants and measurement ranges

Each indicator has a predefined set of thresholds identified by a letter or number. The images, dimensions, layouts and values below are taken from the official Thermax SM046 Rev 10 catalogue.

Thermax PRECISION 11-level temperature indicator, 75–100 °C range

Thermax PRECISION 11-level temperature indicator, 200–300 °C range

THERMAX 11-level PRECISION

11 measurement points

The highest precision in the Thermax range: 11 sensing areas, with 2.5 °C increments in the lower temperature ranges.

How it works

The self-adhesive indicator fields turn permanently black in sequence, starting at the lowest temperature threshold reached. The last black field shows the highest temperature threshold reached; the record remains visible after cooling.

Application and use

Attach the indicator to a clean, dry surface at a location representative of the temperature being monitored — for example, on a motor housing, bearing housing, transformer or workpiece in an oven. Take the reading once the indication has stabilised.

Dimension: 55 × 20 mm
Layout: Vertical
Scale: °C
Packaging: 25 pcs

Self-adhesive, battery-free · 11 irreversible temperature points

Range 1

2527.53032.53537.54042.54547.550

Range 2

5052.55557.56062.56567.57072.575

Range 3

7577.58082.58587.59092.59597.5100

Range 4

100105110115120125130135140145150

Range 5

150155160165170175180185190195200

Range 6

200210220230240250260270280290300

Range	1	2	3	4	5	6
1.	25	50	75	100	150	200
2.	27.5	52.5	77.5	105	155	210
3.	30	55	80	110	160	220
4.	32.5	57.5	82.5	115	165	230
5.	35	60	85	120	170	240
6.	37.5	62.5	87.5	125	175	250
7.	40	65	90	130	180	260
8.	42.5	67.5	92.5	135	185	270
9.	45	70	95	140	190	280
10.	47.5	72.5	97.5	145	195	290
11.	50	75	100	150	200	300

All values in °C.

Enquire about this variant

THERMAX 10-level

10 measurement points

The most detailed view of temperature history, with ten sensing areas.

How it works

Application and use

Dimension: 51 × 18 mm
Layout: Vertical
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 10 irreversible temperature points

Range A

37404446495460626571

Range B

7782889399104110116121127

Range C

132138143149154160166171177182

Range D

188193199204210216224232241249

Range	A	B	C	D
1.	37	77	132	188
2.	40	82	138	193
3.	44	88	143	199
4.	46	93	149	204
5.	49	99	154	210
6.	54	104	160	216
7.	60	110	166	224
8.	62	116	171	232
9.	65	121	177	241
10.	71	127	182	249

All values in °C.

Enquire about this variant

THERMAX 8-level

8 measurement points

Eight temperature thresholds on one label for a clear indication of the maximum temperature reached.

How it works

Application and use

Dimension: 51 × 18 mm
Layout: Vertical
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 8 irreversible temperature points

Range A

3740434649546065

Range B

717782889399104110

Range C

116121127132138143149154

Range D

160166171177182188193199

Range E

204210216224232241249254260

Range	A	B	C	D	E
1.	37	71	116	160	204
2.	40	77	121	166	210
3.	43	82	127	171	216
4.	46	88	132	177	224
5.	49	93	138	182	232
6.	54	99	143	188	241
7.	60	104	149	193	249
8.	65	110	154	199	254
9.	—	—	—	—	260

All values in °C.

Enquire about this variant

THERMAX 6-level MINI

6 measurement points

A compact horizontal temperature indicator strip for spaces where a standard label is too large.

How it works

Application and use

Dimension: 12 × 32 mm
Layout: Horizontal
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 6 irreversible temperature points

Range 1

293334374042

Range 2

444649546062

Range 3

657177828893

Range 4

99104110116121127

Range 5

132138143149154160

Range 6

166171177182188193

Range 7

199204210216224232

Range 8

241249254260280290

Range	1	2	3	4	5	6	7	8
1.	29	44	65	99	132	166	199	241
2.	33	46	71	104	138	171	204	249
3.	34	49	77	110	143	177	210	254
4.	37	54	82	116	149	182	216	260
5.	40	60	88	121	154	188	224	280
6.	42	62	93	127	160	193	232	290

All values in °C.

Enquire about this variant

THERMAX 5-level

5 measurement points

A vertical temperature indicator strip with five sensing areas and a scale in °C and °F.

How it works

Application and use

Dimension: 51 × 18 mm
Layout: Vertical
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 5 irreversible temperature points

Range A

3740434649

Range B

4954606571

Range C

7782889399

Range D

104110116121127

Range E

132138143149154

Range F

160166171177182

Range G

188193199204210

Range H

216224232241249

Range I

249254260280290

Range S

2933343740

Range	A	B	C	D	E	F	G	H	I	S
1.	37	49	77	104	132	160	188	216	249	29
2.	40	54	82	110	138	166	193	224	254	33
3.	43	60	88	116	143	171	199	232	260	34
4.	46	65	93	121	149	177	204	241	280	37
5.	49	71	99	127	154	182	210	249	290	40

All values in °C.

Enquire about this variant

THERMAX 5-level CLOCK

5 measurement points

A circular indicator with five sensing areas, designed for small surfaces.

How it works

Application and use

Dimension: Ø 14 mm
Layout: Circular
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 5 irreversible temperature points

Range 1

4043464954

Range 2

6065717782

Range 3

889399104110

Range 4

116121127132138

Range 5

143149154160166

Range 6

171177182188193

Range 7

199204210216224

Range 8

232241249254260

Range 9

2933343740

Range	1	2	3	4	5	6	7	8	9
1.	40	60	88	116	143	171	199	232	29
2.	43	65	93	121	149	177	204	241	33
3.	46	71	99	127	154	182	210	249	34
4.	49	77	104	132	160	188	216	254	37
5.	54	82	110	138	166	193	224	260	40

All values in °C.

Enquire about this variant

THERMAX 4-level

4 measurement points

Four large sensing areas provide a quick, unambiguous reading.

How it works

Application and use

Dimension: 23 × 45 mm
Layout: Horizontal
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 4 irreversible temperature points

Range A

37444954

Range B

60657177

Range C

82889399

Range D

104110116121

Range E

127132138143

Range F

149154160166

Range G

171177182188

Range H

193199204210

Range I

216224232241

Range J

249260280290

Range	A	B	C	D	E	F	G	H	I	J
1.	37	60	82	104	127	149	171	193	216	249
2.	44	65	88	110	132	154	177	199	224	260
3.	49	71	93	116	138	160	182	204	232	280
4.	54	77	99	121	143	166	188	210	241	290

All values in °C.

Enquire about this variant

THERMAX 4-level MICRO

4 measurement points

A miniature label for electronics, small components and hard-to-reach areas.

How it works

Application and use

Dimension: 4 × 11 mm
Layout: Horizontal
Scale: °C and °F
Packaging: 10 pcs

Self-adhesive, battery-free · 4 irreversible temperature points

Range 1

40424446

Range 2

49546065

Range 3

71778288

Range 4

9399104110

Range 5

116121127132

Range 6

138143149154

Range 7

160166171177

Range 8

182188193199

Range 9

204210215224

Range	1	2	3	4	5	6	7	8	9
1.	40	49	71	93	116	138	160	182	204
2.	42	54	77	99	121	143	166	188	210
3.	44	60	82	104	127	149	171	193	215
4.	46	65	88	110	132	154	177	199	224

All values in °C.

Enquire about this variant

Official Thermax hermetically sealed single-level temperature indicator before and after activation

THERMAX hermetically sealed single-level, made to order

1 level

A single sensing area turns permanently black when the specified maximum temperature is reached.

Dimension: 12 × 13 mm
Indication: Clear → black
Scale: °C and °F
Packaging: 50 pcs

Available temperature thresholds (°C):

293334374042434446495460626571778082889399104110116121127132138143149154160166171177182188193199204210216224232241249254260280290

Enquire about this variant

Summary

Thermax self-adhesive temperature indicator strips 25–300 °C

No power required

Operate without batteries, wiring or continuous operator supervision.

Maximum temperature memory

The blackened field remains on the strip as evidence that the temperature threshold was exceeded.

Range selection

We help you select the right variant for your machine, process, packaging or shipment.

Request a wholesale quote and assistance in selecting the right variant for your process.

Request a quote

Pre-purchase support

Frequently asked questions

How do you read a Thermax temperature indicator strip?

The highest temperature field that has permanently turned black indicates the temperature reached. If the next field remains light, the actual temperature was between these two thresholds.

Can a Thermax strip be reused?

No. The colour change is irreversible, so the strip provides a single-use record of the highest temperature reached and can be attached to inspection records.

Does Thermax require batteries or activation?

No. The strip starts monitoring temperature once applied and requires no batteries, wiring, apps or manual activation.

Where should a temperature indicator strip be applied?

Apply the strip to a clean, dry surface as close as possible to the point where you want to monitor temperature. Avoid locations where the label could suffer mechanical damage.

How do you choose the number of temperature fields and the temperature range?

A single-point indicator monitors one threshold. A multi-point version is better suited to estimating the maximum temperature and identifying which thresholds it fell between.

Does the strip measure air or surface temperature?

The strip responds primarily to the temperature of the surface to which it is applied. The result depends on its position, thermal contact and the time needed to reach thermal equilibrium.

How do temperature indicator labels differ from a pyrometer or thermocouple?

Temperature indicator labels (self-adhesive thermal labels) operate continuously without power, recording the maximum temperature between readings. A pyrometer and thermocouple show the temperature only at the time of measurement.

Can a Thermax strip serve as a temperature indicator seal in warranty procedures?

Yes. A strip applied to a motor, pump or gearbox before dispatch permanently records overheating. A blackened field provides evidence when assessing warranty claims and protects the manufacturer against unjustified claims.

Range	A	B	C	D
1.	37	77	132	188
2.	40	82	138	193
3.	44	88	143	199
4.	46	93	149	204
5.	49	99	154	210
6.	54	104	160	216
7.	60	110	166	224
8.	62	116	171	232
9.	65	121	177	241
10.	71	127	182	249

Range	A	B	C	D	E
1.	37	71	116	160	204
2.	40	77	121	166	210
3.	43	82	127	171	216
4.	46	88	132	177	224
5.	49	93	138	182	232
6.	54	99	143	188	241
7.	60	104	149	193	249
8.	65	110	154	199	254
9.	—	—	—	—	260

Range	1	2	3	4	5	6	7	8
1.	29	44	65	99	132	166	199	241
2.	33	46	71	104	138	171	204	249
3.	34	49	77	110	143	177	210	254
4.	37	54	82	116	149	182	216	260
5.	40	60	88	121	154	188	224	280
6.	42	62	93	127	160	193	232	290

Range	A	B	C	D	E	F	G	H	I	S
1.	37	49	77	104	132	160	188	216	249	29
2.	40	54	82	110	138	166	193	224	254	33
3.	43	60	88	116	143	171	199	232	260	34
4.	46	65	93	121	149	177	204	241	280	37
5.	49	71	99	127	154	182	210	249	290	40

Range	1	2	3	4	5	6	7	8	9
1.	40	60	88	116	143	171	199	232	29
2.	43	65	93	121	149	177	204	241	33
3.	46	71	99	127	154	182	210	249	34
4.	49	77	104	132	160	188	216	254	37
5.	54	82	110	138	166	193	224	260	40

Range	A	B	C	D	E	F	G	H	I	J
1.	37	60	82	104	127	149	171	193	216	249
2.	44	65	88	110	132	154	177	199	224	260
3.	49	71	93	116	138	160	182	204	232	280
4.	54	77	99	121	143	166	188	210	241	290

Range	1	2	3	4	5	6	7	8	9
1.	40	49	71	93	116	138	160	182	204
2.	42	54	77	99	121	143	166	188	210
3.	44	60	82	104	127	149	171	193	215
4.	46	65	88	110	132	154	177	199	224

Range	A	B	C	D
1.	37	77	132	188
2.	40	82	138	193
3.	44	88	143	199
4.	46	93	149	204
5.	49	99	154	210
6.	54	104	160	216
7.	60	110	166	224
8.	62	116	171	232
9.	65	121	177	241
10.	71	127	182	249

Range	A	B	C	D	E
1.	37	71	116	160	204
2.	40	77	121	166	210
3.	43	82	127	171	216
4.	46	88	132	177	224
5.	49	93	138	182	232
6.	54	99	143	188	241
7.	60	104	149	193	249
8.	65	110	154	199	254
9.	—	—	—	—	260

Range	1	2	3	4	5	6	7	8
1.	29	44	65	99	132	166	199	241
2.	33	46	71	104	138	171	204	249
3.	34	49	77	110	143	177	210	254
4.	37	54	82	116	149	182	216	260
5.	40	60	88	121	154	188	224	280
6.	42	62	93	127	160	193	232	290

Range	A	B	C	D	E	F	G	H	I	S
1.	37	49	77	104	132	160	188	216	249	29
2.	40	54	82	110	138	166	193	224	254	33
3.	43	60	88	116	143	171	199	232	260	34
4.	46	65	93	121	149	177	204	241	280	37
5.	49	71	99	127	154	182	210	249	290	40

Range	1	2	3	4	5	6	7	8	9
1.	40	60	88	116	143	171	199	232	29
2.	43	65	93	121	149	177	204	241	33
3.	46	71	99	127	154	182	210	249	34
4.	49	77	104	132	160	188	216	254	37
5.	54	82	110	138	166	193	224	260	40

Range	A	B	C	D	E	F	G	H	I	J
1.	37	60	82	104	127	149	171	193	216	249
2.	44	65	88	110	132	154	177	199	224	260
3.	49	71	93	116	138	160	182	204	232	280
4.	54	77	99	121	143	166	188	210	241	290

Range	1	2	3	4	5	6	7	8	9
1.	40	49	71	93	116	138	160	182	204
2.	42	54	77	99	121	143	166	188	210
3.	44	60	82	104	127	149	171	193	215
4.	46	65	88	110	132	154	177	199	224

Range	A	B	C	D
1.	37	77	132	188
2.	40	82	138	193
3.	44	88	143	199
4.	46	93	149	204
5.	49	99	154	210
6.	54	104	160	216
7.	60	110	166	224
8.	62	116	171	232
9.	65	121	177	241
10.	71	127	182	249

Range	A	B	C	D	E
1.	37	71	116	160	204
2.	40	77	121	166	210
3.	43	82	127	171	216
4.	46	88	132	177	224
5.	49	93	138	182	232
6.	54	99	143	188	241
7.	60	104	149	193	249
8.	65	110	154	199	254
9.	—	—	—	—	260

Range	1	2	3	4	5	6	7	8
1.	29	44	65	99	132	166	199	241
2.	33	46	71	104	138	171	204	249
3.	34	49	77	110	143	177	210	254
4.	37	54	82	116	149	182	216	260
5.	40	60	88	121	154	188	224	280
6.	42	62	93	127	160	193	232	290

Range	A	B	C	D	E	F	G	H	I	S
1.	37	49	77	104	132	160	188	216	249	29
2.	40	54	82	110	138	166	193	224	254	33
3.	43	60	88	116	143	171	199	232	260	34
4.	46	65	93	121	149	177	204	241	280	37
5.	49	71	99	127	154	182	210	249	290	40

Range	1	2	3	4	5	6	7	8	9
1.	40	60	88	116	143	171	199	232	29
2.	43	65	93	121	149	177	204	241	33
3.	46	71	99	127	154	182	210	249	34
4.	49	77	104	132	160	188	216	254	37
5.	54	82	110	138	166	193	224	260	40

Range	A	B	C	D	E	F	G	H	I	J
1.	37	60	82	104	127	149	171	193	216	249
2.	44	65	88	110	132	154	177	199	224	260
3.	49	71	93	116	138	160	182	204	232	280
4.	54	77	99	121	143	166	188	210	241	290

Range	1	2	3	4	5	6	7	8	9
1.	40	49	71	93	116	138	160	182	204
2.	42	54	77	99	121	143	166	188	210
3.	44	60	82	104	127	149	171	193	215
4.	46	65	88	110	132	154	177	199	224