FireAngel smoke alarm (bottom) and carbon monoxide detectors as fitted in modern caravans/ motorhomes fitted high up as the gases are lighter than air Stock Photo - Alamy
FireAngel Pro Connected Battery & mains-powered Interlinked Smart smoke alarm | DIY at B&Q
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