Cover snaps onto base no screws required. Cover has twistouts on all sides. Rectangular KO in base for extenstion to wall box. Used with 2700 2800 2900 and NM2000 Series Raceways. 4 3/4'' L x 3'' W x 1 3/4'' D 121mm L x 76mm W x 44mm D. 1Gang.This product meets the material restrictions of RoHS