RFID technology without contact, auto-sensing RF reader, sensing distance of about 3-5CM; with LCD clock display, card reader prompts; durable, one plastic lamps, sealed waterproof, shockproof, dustproof, ultra-low-power design, Battery life can be continuously reader 400,000; 10,000 records memory (expandable); low temperature ultra-low power design, can store 10,000 records (scalable) programming with vandalism / battery test / replacement time error such as memory and recording functions. (Which patrol with charging function, self-charging, no need to replace the battery, with charger) Material: metal Weight: 210g; Dimensions: 15 * 4.3 * 2.6cm; working environment: -30 ℃ - + 80 ℃ Memory: 4M Flash 1 million data (expandable); Power: 5 # battery size double 3.6V lithium battery