FIREANGEL ST-622: Smoke Alarm incl. 10 years battery at reichelt elektronik
FireAngel Optical Smoke Alarm with 10 Year Sealed For Life Battery, FA6620-R-T2 (ST-622 / ST-620 replacement, new gen) - Twin Pack , White : Amazon.co.uk: DIY & Tools
How to Install a FireAngel ST-620 smoke alarm - YouTube