AA step up in strength and durability. Anodized aluminum sideplates, 2 3/8" aluminum sheave, bushing, and stainless steel axle.Part Number: RP102 (435425), RP103 (435430)Weight: 0.45 lbsMBS: 6,000 lbs (26kN)Rope Capacity: 5/8"Side Plates: Anodized AluminumMechanics: Bushing (435425), Bearing (435430)Sheave: 2 3/8" AluminumAxle: Stainless SteelSize (in): 4.25x3.25Efficiency: 91.4% (435425), 95.6% (435430)