The Kidde 10Y29RB 10-Year Optical Smoke Alarm has a test/hush button for regular testing of the smoke alarm function, it also allows nuisance alarms to be temporarily silenced. Easy to install and can be used in most locations in the home, particularly in bedrooms and living areas. Sealed-in lithium battery that never needs replacing. Approved to EN 14604, and has a 10-year warranty (including the battery).