This Home Protect Hallways smoke alarm is a long-life, optical smoke alarm with a sealed-in Lithium battery, that lasts the full 10-year life and never needs to be replaced. It is ideal for use in hallways and landings and can either be wall-mounted (between 10cm and 30cm from the ceiling) or if ceiling- mounted (at least 10cm from the corner with the nearest wall). The single screw mounting bracket, and full fitting instructions are included – very easy to install and set up. A high intensity emergency escape light illuminates to help guide you to safety and a hush button allows nuisance alarms to be temporarily silenced. It has an end-of-life warning signal that alerts you after 10 years, when it is time to replace. Certified by UL to EN14604:2005, CE tested and certified. It is fully tested before leaving the factory. Any questions not answered in the Q+A or PDF call Kidde on 0800 917 0722 (UK) or 1 800 818 601 (S. Ireland). See PDF for full product details. Hush button operation. Test button operation. 10 year sensor life. Batteries required: 1 x Li-Ion (included) . Size H13, W13, D3.3cm. Weight 0.2kg. Manufacturer's 10 year guarantee.