The detector features a rectangular case, with rounded corners and on the the front, the device is covered by lots of puncture holes, with a solid circular button in the middle which is surrounded by a small canal to make way for the LED light to break through it looks surprisingly similar to a speaker. Turn the device around and you can see four narrow, but fairly long ventilation holes on the edges, four holes for ceiling mounting, a battery door and a micro USB connector in case the smoke detector needs servicing. This is available for the battery powered Nest Protect, but, of course, you can also purchase the wired variant, which will have additional AC connector pins on the back side to attach a 230V cable connector. The device itself is not really bigger than the average smoke detector from the market, measuring 1. 63 x 5. 28 inches and the install process follows the same steps: after choosing the rooms in which you’re going to install the Nest Protect at least in every room which has a fuel burning appliance, you need to make sure there is a minimum of 10 feet from any cooking appliance and avoid placing it on a corner you can choose either a wall or the ceiling.