Extech 39240 Waterproof Stem Thermometer

Fits pocket temperature checks on liquids and solids that need a waterproof digital stem thermometer — −40 to 200 °C (−40 to 392 °F), 0.1° resolution, 2.75 in (70 mm) stainless stem, MAX/MIN and Hold — not a dewpoint calibrator or panel transmitter.

Key advantages

Range / resolution — −40 to 392 °F (−40 to 200 °C), °C/°F switchable; 0.1 °F/°C resolution.
Basic accuracy — ±1 °C / ±2 °F (Extech product page basic accuracy).
Stem — 2.75 in (70 mm) stainless-steel contact stem for liquids and frozen solids.
Functions — Digital segment LCD; MAX/MIN recall; Data Hold; Auto power Off.
Form / sealing — Waterproof housing (fully submersible per OEM datasheet); 5.9 × 0.8 × 0.7 in (150 × 20 × 18 mm); 0.7 oz (20 g); 1 × LR44; CE.

Typical applications

Spot checks of chilled or hot liquids where a pocket stem thermometer is enough.
Frozen-food and cold-store surface/contact checks within −40 to 200 °C.
Field service kits that need MAX/MIN recall and Data Hold without a logger.
Washdown or wet-area checks where OEM waterproof / submersible housing is specified.

Selection guide

Temperature band — Confirm process points sit in −40 to 200 °C (−40 to 392 °F) before RFQ.
Stem length — Fixed 2.75 in (70 mm) stainless contact stem — not a remote-cable probe.
Accuracy need — Basic ±1 °C / ±2 °F class; order a higher-accuracy RTD/thermocouple system if you need calibration-lab uncertainty.
Unit preference — °C/°F switchable; state the display unit your SOP uses.
Power — Single LR44 (1.5 V) button cell — plan spares for continuous daily use.

Common mistakes

Expecting a dewpoint or humidity calibrator — 39240 is a waterproof stem thermometer only.
Assuming a long penetration cable like TM26 — stem is integral 70 mm stainless.
Treating basic ±1 °C / ±2 °F as a certified reference without a cal certificate path.
Ordering for permanent panel mount — this is a pocket handheld, not a process transmitter.

When to RFQ / what to tell us

Media (liquid / solid), expected temperature band, and °C vs °F preference.
Whether waterproof/submersible use and MAX/MIN/Hold are required.
Quantity, ship-to, and spare LR44 or protective-case needs if known.

Request a Quote · Get selection help

Specs

Spec	Value
SKU	34228
Brand	Extech
Model	39240
Product type	stem_thermometer
Measuring range	−40 to 392 °F (−40 to 200 °C), °C/°F switchable
Accuracy	±1 °C / ±2 °F (Extech product page basic accuracy)
Resolution	0.1 °F/°C
Sensor type	2.75 in (70 mm) stainless-steel contact stem
Display	Digital segment LCD; MAX/MIN recall; Data Hold; Auto power Off
Supply voltage	1 × LR44 (1.5 V) button cell battery
Ingress protection	Waterproof housing (fully submersible per OEM datasheet)
Dimensions	5.9 × 0.8 × 0.7 in (150 × 20 × 18 mm)
Weight	0.7 oz (20 g)
Approvals	CE
Notes	Specs from Extech Product DATASHEET R2 (03/21/07) + extech.com/flir.com 39240 product pages.

Documents

Extech 39240 user manual (PDF)

FAQ

Q: Is 39240 a dewpoint calibrator? A: No — it is a waterproof digital stem thermometer (−40 to 200 °C). For dewpoint calibration use a dedicated dewpoint calibrator SKU.

Q: Stem length and sealing? A: 2.75 in (70 mm) stainless contact stem; housing is waterproof / fully submersible per OEM datasheet.

Q: What should I send for a quote? A: Temperature band, media, quantity, ship-to. Compatible with systems using Extech 39240 — we do not claim authorized-dealer status.