B121ADJ BOX, 1-GANG PVC 21CI | Provides simple installation and allows adjustment from 0 to 1-3/4 in 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 D x 3-7/8 in x 3-3/4 in. Permissible for use with 90 deg C connectors. Satisfies NEC 370-20. UL listed 5Z74 and classified 2 Hr W/C.