Product Features:
Stainless Steel Base, Head post & Hub
Roller are not ball bearing so they will not have any issues that come with ball bearing rollers
Side-plates: UV-stabilized with reinforced nylon composite for maximum protection 
Block Connection: Base Mounting
Becket: No
Mounting screws are NOT included
Specifications:
Sheave Diameter: ~2.75" (70mm)
Max. Line (Rope) Diameter: 0.63" (16mm)
Max. Working Load (MWL): 8377lb (3800kg) 
Breaking Load: 3968lb (1800kg) 
Weight: 1lb 2.4oz (520gr)
Base plate: 4.5x3.4" (114x85mm)
Mounting holes on center: Short side:2.6" (66mm). Long-side: 3.8" (96mm)