The base appears to be designed to fit into a flat wall or ceiling, not an existing electrical box. I bought four and was only able to install one on the largest electrical box. They work well on a smooth wall or ceiling. I replace the wired system. The intention was to install them so that they cover the holes in the wall that lead to the junction boxes. Did not work. I had to buy another brand for that. One without a 10-year battery. What to do with a 10 year old battery? Sensors serve about 10 years. We had smoked a pot on the stove. It filled the whole house with smoke. None of the five 20-year-old smoke detectors went off. All "tested" fine then.
Interconnect Lithium Battery Powered Kidde Smoke & Carbon Monoxide Detector with Voice Alert - Combination Smoke & CO Alarm
9 Review
π° Ensure Your Family's Safety: DIY Lead in Drinking Water Test Kit for City or Well Water - Quick 10 Minute Test - Single Pack
9 Review
Hygienic shower Grohe BauCurve 123072, chrome
10 Review
Xiaomi Mi Smart Sensor Set
45 Review
Lingito Rain Poncho: Buy 5, 10, or π§οΈ 15 Packs - Disposable Emergency Rain Ponchos for Ultimate Protection
8 Review
Be Prepared For Anything With Quakehold! 70500 Evacuation Essentials Kit
9 Review
π§οΈ Premium Quality Disposable Rain Ponchos for Adults / Kids (6 Pack) - 50% Thicker Emergency Ponchos for Ultimate Waterproof Protection
8 Review
π² Augason Farms Variety Pail Emergency Food Supply (Lunch and Dinner) - 4-Gallon Pail
8 Review