The GL09 GSM Alarm Module is an SMS 8-channel mobile phone controlled battery-powered module, designed to enhance your security system by sensing intrusion (sensors not provided) and alerting via SMS text message. Compact size of 66 * 62 * 22mm/2.6 * 2.4 * 0.9in, makes it easy to install and use, with external aerial to ensure good signal reception. The alarm module takes a full-sized SIM card and the alarm module can be disables remotely via SMS, as well as battery voltage checked. Unit has a low power mode ideal for use with a solar panel/battery setup for off-grid monitoring of remote premises. These units are brand new in box/never used as they were bought for a cancelled project. Priced to sell.