Guide TK421 Thermal Imaging Monocular

The Guide TK421 is a compact thermal monocular featuring a high‑resolution 400×300 VOx sensor with a 17 µm pixel pitch and a sensitive NETD of ≤ 30 mK. It delivers vivid thermal images to a crisp 0.4″ FLCOS display at 1280×960 resolution and 50 Hz refresh rate.

Its 25 mm f/1.1 lens offers a field of view of approx. 19 m × 14 m at 100 m. With optical zoom starting at 1.7× and up to 4× digital zoom (total ~6.8×), it enables effective detection—up to ~700 m for human-sized objects and ~1,700 m for vehicles—even in low-light settings.

About the Guide TK Series

The TK series provides a budget-friendly entry point to thermal imaging, offering essential features like live Wi‑Fi streaming via the TargetIR app, continuous zoom, hotspot tracking, and fast startup (around 2 s). The durable IP66-rated housing ensures rugged performance in the field.

Key Features

• 400×300 VOx sensor, 17 µm pixel pitch; NETD ≤ 30 mK
• 25 mm f/1.1 objective lens, manual focus
• Field of view at 100 m: approx. 19 m × 14 m
• Magnification: 1.7× optical; up to 6.8× combined zoom
• Detection range: human ~700 m; vehicle ~1,700 m
• Display: 0.4″ FLCOS, 1280×960 resolution, 50 Hz refresh
• Color palettes: White Hot, Black Hot, Iron Red, Blue Hot, Green Hot, Adjustable Red Hot
• Zoom: continuous up to 6.8× (1×–4× digital)
• Battery: built-in 2× 18650 cells; runtime approx. 5 hours
• Features: PIP zoom, stadiametric ranging, laser pointer (up to ~200 m), flashlight
• Connectivity: Wi‑Fi streaming, mobile app control
• Housing: IP66-rated waterproof and shock-resistant; 1 m drop-tested
• Weight: ~470 g; Dimensions: 192 × 65 × 71 mm

About Guide Sensmart

Guide Sensmart (Guide Infrared) is a global thermal imaging brand with over two decades of experience. Serving more than 70 countries, Guide delivers innovative yet accessible thermal optics designed for outdoor, inspection, and general-purpose applications.

What’s in the Box

• Guide TK421 Thermal Monocular
• Wrist strap
• Carry pouch & lens cover
• USB‑C charging cable
• Quick Start Guide & Warranty Card

Warranty

The TK421 is backed by a 2‑year manufacturer warranty, with support available through Guide’s global service network.