Guide TD421 LRF

The Guide TD421 LRF is a reliable thermal monocular with a built-in 600 m laser rangefinder, delivering precise distance measurements alongside crisp thermal imaging. It features a 384 × 288 VOx sensor with 12 µm pixel pitch and a thermal sensitivity of ≤35 mK, ensuring detailed performance in varied outdoor conditions. The thermal image is presented on a 0.23″ AMOLED display with 640 × 400 resolution and a smooth 50 Hz refresh rate.

The device is equipped with a 25 mm f/1.1 lens, providing a field of view of approximately 18 m × 14 m at 100 m and a detection range of up to 1,300 m. The TD421 LRF offers 1.9× to 7.6× magnification for flexible mid- to long-range observation.

About the Guide TD Gen2 LRF Series

The TD Gen2 LRF series combines the rugged reliability of Guide's thermal monoculars with the added benefit of integrated rangefinding. Each unit is designed for users who need accurate distance estimation and stable image performance in compact, field-ready housings. With IP66-rated protection, fast startup, and 10-hour battery life, these devices are built for dependable use in all conditions.

Key Features

• 384 × 288 VOx thermal sensor, 12 µm; NETD ≤ 35 mK
• 25 mm f/1.1 objective lens with manual focus
• Field of view at 100 m: approx. 18 m × 14 m
• Magnification: 1.9× to 7.6× optical
• Detection range: up to 1,300 m
• Integrated laser rangefinder: up to 600 m
• Display: 0.23″ AMOLED, 640 × 400, 50 Hz refresh rate
• Color palettes: White Hot, Black Hot, Red Hot, Green Hot, Iron Red, Blue Hot, Sepia
• Eyepiece: 12 mm eye relief, diopter adjustable −4 to +2
• Connectivity: Wi‑Fi 2.4 GHz and USB-C interface
• Battery: Single 18650 battery, up to 10 hours operation
• Housing: IP66 water- and dust-resistant
• Weight: 360 g; Dimensions: 150 × 75 × 74 mm

About Guide Sensmart

Guide Sensmart is a global leader in infrared thermal imaging solutions. As part of Guide Infrared, the company serves over 70 countries with innovative, affordable, and durable optics for outdoor and industrial applications. With decades of R&D and manufacturing experience, Guide is trusted by professionals and enthusiasts alike.

What’s in the Box

• Guide TD421 LRF Thermal Monocular
• Lens cover and lanyard
• Wrist strap
• Carry bag and eye mask
• Battery charger and 18650 rechargeable battery
• USB‑C cable
• Quick start guide and warranty card

Warranty

The TD421 LRF comes with a 2-year manufacturer warranty and access to service through Guide’s international support network.