The PRG-340 includes a digital compass, altimeter/barometer, and thermometer as part of its Triple Sensor (Version 3) suite. The digital compass measures direction from 0 to 359° with 16-point readouts, bidirectional calibration, and magnetic declination correction. The altimeter tracks elevation from -700 to 10,000m (-2,300 to 32,800 ft.) with trek logging across up to 14 records. The barometer monitors atmospheric pressure from 260 to 1,100 hPa with a 42-hour tendency graph and a pressure alarm that triggers on significant pressure changes. The thermometer reads ambient temperature from -10 to 60°C (14 to 140°F).

The PRG-340T-7 (Silver) replaces the bio-based urethane band of the PRG-340-1 and PRG-340-3 with a titanium link bracelet and a one-touch fold-over deployant clasp. The titanium bracelet increases total watch weight from approximately 54g to 87g and adjusts to fit wrists from 145 to 215mm. All sensor functions, case dimensions, water resistance, and solar power specs are identical across all three variants. Color accents differ by variant: the PRG-340-1 uses red, the PRG-340-3 uses yellow and orange, and the PRG-340T-7 uses orange on a silver-tone titanium case.

Tough Solar uses a photovoltaic cell beneath the watch face to convert any light source into electrical energy stored in a rechargeable battery. Indoor fluorescent and LED lighting both work, though direct sunlight charges the battery fastest. In power-saving mode, the Casio PRG-340 retains approximately 7 months of reserve. A battery level indicator on the display shows your remaining charge so you are never caught off guard in the field.

A barometric altimeter watch like the PRG-340 measures altitude by detecting changes in atmospheric pressure, making it fast, completely offline, and accurate at moderate elevations without satellite dependency. GPS watches calculate altitude via satellite triangulation, which can be slower to update and less accurate in dense canopy, canyons, or indoors. The tradeoff is that barometric altimeters require periodic calibration against a known elevation and can drift with weather-driven pressure changes, which is exactly why the PRG-340 also includes a pressure tendency alarm to help distinguish weather changes from altitude changes.

Yes, the PRG-340 is a purpose-built field tool designed for demanding outdoor professionals. Its glove-compatible buttons, direct-access sensor functions, rotating bezel for bearing memory, and 10-bar water resistance make it a practical choice for law enforcement patrol, military land navigation, and search and rescue operations. The digital compass with magnetic declination correction and the altimeter with 14-trek logging support both active navigation and field situation reporting. At roughly 54g in the resin-band variants, it adds minimal weight to an already loaded kit.