Leviton 40050-MHG Hinged Cover For Demarc Or M Blocks, Grey Snaps into the right side fanning strip of 25 and 50-pair M blocks Protects wiring from dust, dirt, and incidental shorting Allows wires to be routed from both left and right sides Color Grey 10" H x 2 7/16" W x 1 1/2" D