50-pair modular 66-idc wiring block features: terminates solid copper wire category 3 24 awg to category-6 23 awg quick-connect 66-idc flame retardant thermoplastic construction 50-pair modular split 66-idc type wiring blocks 2 1/8inch(w) x 10inch(h) x 1 1/8inch(d) used in equipment rooms and wiring closets to connect telephone systems, pbx systems and other low-speed terminal equipment