The Blaupunkt Mini ISD-SD1 smoke detector is relatively small with a size of 7 x 7 x 5 cm. You attach this compact smoke detector to your ceiling. When the sensor detects smoke, an audible signal sounds 85 dB. The smoke detector has a built-in battery that lasts up to 10 years. The battery is not interchangeable. To check if the smoke alarm is still working properly, press the test switch at least once every time.