Patented design provides simple, goof-proof installation and allows the installer to adjust the box to any thickness with the turn of a screw. Clip the included bracket onto any stud, mounts square and secure every time. Securing the bracket to the stud ensures that the box will not move. Comes preset at 1/2 in 3-3/8 in depth x 3-7/8 in x 3-3/4 in Satisfies NEC 370-20. UL Listed 5Z74 and classified 2 Hr W/C.