The Red Smoke Alarms RFMDUAL is a photoelectric flush mount smoke alarm that provides versatile functionality. It can serve as a 240V mains powered alarm with a 10-year lithium battery backup. It can also be interconnected with other 240V Red smoke/heat alarms or function as a standalone 10-year lithium battery smoke alarm with the option for wireless interconnection using an RF module. The alarm is designed for convenient installation with a 90mm cut out hole. The flush mount design of the smoke alarm ensures that it remains level with the ceiling, providing both effective protection and a discreet appearance. Features Main Power source: 240V or 10 Year 3V Lithium Battery (CSIRO certified as either or) Backup Battery: 10 Year 3V Lithium Battery (When on 240V) Battery Life: 10 Year 90mm Flush Mount Alarm Volume : > 85db at 3 metres Sound Pattern: ISO8201 Wired/Wireless (with RF Module ) Interconnection: up to 40 Alarms Comply with: AS3786:2014