Thommen® TX 22 Mechanical Altimeter/Barometers :
Pocket-sized and lightweight, these Thommen® mechanical altimeter/barometers feature a 19 jeweled, temperature-compensated precision movement, aneroid capsules, scratch-resistant plastic faces, and extra tough Delrin plastic cases. All models include lanyard and multi-holder which attaches to any vertical or horizontal surface. No batteries required.
Altitude range: 0 to 6,000m. Minimum accuracy: ±10m. Minimum graduation: 10m. Temperature range: -20°C to +40°C. Range: 735mbars to 1,050mbars.