1. Size: 107*35mm 2. The shell is made of ABS fire-proof material and its sensitivity meets UL217 standard. 3. Working Voltage: DC9V 1*6F22 Battery 4. Alarm mode: acousto-optic alarm 5. Suitable for indoor families, dance halls, warehouses, etc. Test methods: 1. Button test method. Press the test button on the smoke sensor directly. After a few seconds, the alarm will be sent out directly. 2. Smoke test. Smoke is sprayed through the hole of the smoke sensor. Smoke should not be too thin. After a while, the light on the smoke sensor will start to flicker, and after a while, an alarm will be issued

http://olla.gr/ss-168-first-alert-battery-operated-fire-smoke-alarm-detector-white/