This ultra-compact optical smoke detector provides reliable fire protection in a discreet design. It quickly detects visible smoke and activates a loud 85 dB alarm to alert you of danger.Equipped with a long-lasting 10-year CR2 / 3 AH 3V lithium battery (non-replaceable), this EN14604-certified detector ensures years of dependable performance. The convenient Test / Hush function lets you easily test the alarm or temporarily silence itfor instance, when cooking smoke accidentally triggers it.Specifications:Diameter: 45 mmHeight: 42 mmSound level: 85 dBBattery life: 10 years (non-replaceable lithium battery)Functions: Test / Hush