Features: *Increased antenna control, more stable signal, security precautions no longer dropped. *850/900/1800/1900MHz quad bands, can work in the worldwide GSM networks. *No call charges. The GSM Relay Switch answers the call from authorized number then carries out the turn ON/OFF action on the first 'ring'. *Secure - Using caller-ID for identification, unknown callers are ignored. *Add or remove users by SMS Text command. *No need to provide a remote control or keys for different users. *Up to 200 authorized phone numbers can be configured at the specified time. *The relay action will return a SMS confirmation to the owner or authorized call in number, this function is editable by user. *The relay close or open time is programmable. *Multiple applications. (Gates, bollards, barriers, garage doors, shutters and access doors or machines). Specifications: GSM Frequency: 850/900/1800/1900MHz Digital Output: NC/NO dry contact, 3A/240VAC DC Power Supply: 9-24V DC/2A Power Consumption: 12V input Max. 50mA/Average 25mA SIM Card: Standard SIM Card Antenna: 50Ω SMA Antenna interface Temperature Range: -20~+60°C Humidity Range: Relative humidity 90% Dimensions: Approx. 3.23*2.99*1.06in / 82*76*27mm Package Size: Approx. 19.8*11.2*3cm / 7.79*4.40*1.18cm Package Weight: Approx. 9.27oz / 263g Package List: 1 * GSM Door Opener 1 * Antenna 1 * User Manual Card