This weatherproof outdoor siren needs 130mA. It is 3 5/8 in diameter and 1 9/16 thick. The power supply that is included with the Smarthome SecureLinc Family Security System will only supply enough amperage to drive the internal siren and the weatherproof outdoor siren. The Securelinc only supports one hardwired siren; if you need additional sirens, we recommend using the X10 Monitor Plus Powerhorn Remote Siren. Manufacturer's part number Z-PMSIREN. more info