4" Fire Alarm Box With Mounting Plate, Snap-On Installation To Heavy Duty Telescoping Bracket Allows For Easy Positioning Along Bracket, Can Also Be Mounted Directly To Metal Or Wood Studs, Easily Adjusts From 1/2” To 1-1/2” For Different Depth Wall And Ceiling Applications, Screws Inside Fire Alarm Box Allow For Adjustment After Drywall Or Ceiling Tile Installation, Includes Multiple Knockouts On Each Side Of The Box, Design Provides Built In Far Side Support For 3-5/8” Stud Depths, Powder Coated Inside And Outside Of Box, Includes Depth Stamps Marked Directly On The Product For Easy Positioning, Drop-Wire Attachment Point, 1/2" & 3/4" Knockouts