A photoelectric, 10 year sealed lithium battery smoke alarm. No wiring required for installation and no need to ever change the battery.   The smoke alarm includes a test/hush button and visual indicators. The R10 smoke alarm is approved and certified to meet AS3786:2014. The smoke alarm is 140mm diameter making it a perfect size when replacing faulty or expired alarms. Interconnectable with up to 40 red smoke alarms

• Additional information is for packaging size not product.