Stationery Shop › Smoke Detector and Carbon Monoxide Letter Image 1 of 1 Smoke Detector and Carbon Monoxide Letter £15.00 Letter for agents to send to landlords about the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022. Add To Cart Added! Letter for agents to send to landlords about the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022.