2" drain opening fits PVC or ABS Schedule 40 DWV pipe. Easy to remove knockout, Patent Pending Hammer Valves. Snap-on Faceplate Frame accommodates up to 1" drywall. Box made of high impact polystyrene. Top or Bottom Valve Mount. 4 support brackets included for mounting. Box Dimensions: 8-3/4"W x 7-1/2"H x 3-5/8"D. Faceplate Dimensions: 11-3/4"W x 10-1/8"H.