SPECIFICATIONS: RAMP, PLATFORM, STAIR,Made of Aluminum: Yes, Yes, Yes,Slip-resistant Surface: Yes, Yes, Yes,Weight Capacity (lbs): 1000, 1000, 850,Standard Widths (in): 36 and 48 (Solid Surface), 48, 60, and 72, 36,Standard Lengths (ft): 2, 3, 4, 5, 6, 7, 8