The XAR-A Ammonia (NH3) Gas Detector is a precise gas detector for monitoring ammonia in the ambient air and in the workplace. It has been designed to notify of the presence of NH3 gas. This detector uses 3-electrode electrochemical technology, operating by the diffusion principle, for determining the concentration of ammonia in air samples. XAR-A can implement span calibration（50 PPM calibration NH3 gas）when needed. It has two alarm setpoints: High Alarm (NH3: 50 PPM) and Low Alarm (NH3: 25 PPM). These setpoints are factory set and cannot be changed. XAR-A can be widely used in farms/poultry house, livestock and lab animal facilities, liquid ammonia plants, public toilets, septic tanks, loading rack and storage area, at the vaporizer, injection section and other locations near the ammonia fluid handling equipment, having significant leak probability. It can be used to avoid unhealthy and accidents caused by ammonia produced in the workplaces. NH3 Sensor Specification: Measurement Range : 0 ~ 500 PPM; Resolution : 1.0 PPM; Repeatability : 3% of signal; Sample Method : Diffusion; Temperature Range : -20 to 50°C (-4°F ~ 122°F); Humidity Range : 10 to 90%RH; Response Time : <40 seconds; Operating : -10°C to 50°C (14°F to 122°F), 10~90% RH non-condensing; Power Supply : Four AA Alkaline Batteries; Dimensions : 75x165x25 mm (2.95x6.49x0.98"); Weight : 125 grams (4.41 oz.) without batteries. MATERIALS SUPPLIED: (1) XAR-A NH3 Gas Detector; (2) Plastic Toolbox; (3) Telescopic Wand with Tripod; (4) English User Manual.