Heat Seal Tester Models: Compare STH-3, STH-3A, and STH-5

All three KHT STH heat seal testers comply with ASTM F88 and F2029. The right model depends on your testing volume, temperature gradient needs, data logging requirements, and budget. Side-by-side comparison below.

STH-3 manual heat seal tester
Budget Friendly

STH-3

Manual Entry-Level

Straightforward manual heat seal tester for labs that need ASTM F88/F2029 compliance at lowest cost.

Temp Range

0–300°C

Accuracy

±0.5°C

Force

0–600N

Positions

1

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STH-3A 5-position gradient heat seal tester
Most Popular

STH-3A

Digital 5-Position Gradient

Flagship digital gradient model. Test 5 temperatures simultaneously — map your full seal window in one 30-minute run.

Temp Range

0–300°C

Accuracy

±0.5°C

Gradient

5-position

Display

Digital LED

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STH-5 touchscreen IoT heat seal tester
Production Ready

STH-5

Touchscreen IoT

Touchscreen IoT model with programmable profiles, auto data logging, and USB/LAN export for production environments.

Interface

7" Touchscreen

Accuracy

±0.5°C

Export

USB/LAN

Profiles

Programmable

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Model Comparison

STH-3 vs STH-3A vs STH-5: Choose Your Model

All three models comply with ASTM F88 and F2029. The right choice depends on your testing volume, required data output, and IoT integration needs.

FeatureSTH-3 (Manual)STH-3A (Gradient)STH-5 (Touchscreen)
Temperature Range0–300°C0–300°C0–300°C
Temp Accuracy±0.5°C±0.5°C±0.5°C
Sealing Force0–600N0–600N0–600N
Test Positions15 (gradient)1 (programmable)
Control TypeManual dialDigital LED7" Touchscreen
Data LoggingManual recordManual recordAuto USB/LAN
IoT / RemoteNoNoYes
Best ForSmall R&D labsFilm R&D / QCProduction pharma/battery
ASTM F88
ASTM F2029
ISO 11607Compatible

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Heat Seal Tester Models — STH-3, STH-3A, STH-5 | KHT Instrument | KHT Instrument