Our small aluminum pulleys-the MDP and MSP-are strong and lightweight, making them ideal for mini haul systems. The MSP is a single pulley and our MDP is a double rope pulley; both accept ropes up to 11 mm in diameter. Type: Double, Prusik-Minding Weight (g): 82.0 MBS Rating (lb): 4,946 Sheave MBS Rating (lb): 1,236 MBS Rating (kN): 22.0 Sheave MBS Rating (kN): 5.5