301EM : 3.1 lb (1.4 Kg). Sensors available for toxic and combustible gases and refrigerants. Explosionproof sensors for combustible and toxic gases. 301RF, EM: 32° to 100°F (0 to 40°C). Distance To Transmitters: Up to 500 feet (160 m), 200 ft (60.9m) maximum.
eBay