SeeLess has four round smoke alarm mount options and one shaped option. To better understand the round options, check out this SeeLess round smoke detectors platform variety training video.The SLK-SM-500 is a single gang model with a ½” reveal around the device with diameter5.79 inch, height 1.85 inch, inner diameter 5.79 inch The SLK-SM-750 is a single gang model with a slightly bigger reveal of ¾”. SLK-SM1-500 is a deeper single gang mud-in platform with a ½” reveal. It is also commonly used with dome cameras.This smoke alarm mount has been designed around Cosmo smoke alarm. Watch the demo video.The SLK-SM2-1000 is a 2-gang platform with a 1” reveal. It was created mostly for the commercial application requests, where it is required to provide flexibility to integrate alarm monitoring into the smoke detector and to separate the high voltage from low voltage with an inner blank separator partition. To learn about the Nest smoke alarm platform, check out this training video.Single Gang Box Extension Mud Ring is available in SeeLess Accessories to adapt to a standard electrical 4" back box.