... display, with keypad to operate, very easy to operate2, GSM network, no need telephone line3, Know which zone triggers ... also alertTechnical parameter for the gsm alarm system wireless:Operating voltage: Input 100-250V, output 12V. Wireless receiving distance: >100m ... Operating Frequency: 433 MHZ, 850/900/1800/1900MHZStandard kits of the gsm alarm system ...