25.0 Cu. In. 4" dia. round fixture support box for use with nonmetallic sheathed cable - Machine tapped fixture holes, adjustable mounting plate for additional substrate thickness - New and old work residential construction 2 HR fire resistive floors and ceilings (50 lbs. fixture support) - Polycarbonate - thermoplastic box - Size: Depth=2 3/4", Dia=4" - Mount with Internal screws with adjustable slider plate for substrates 1/2" to 1 5/32"