Used on offshore boats where weight and performance are critical. The 100mm range features free-rolling, large-diameter aluminum sheaves with Torlon roller bearings housed in a unique center cage. UV-resistant carbon-black Delrin balls carry sideloads. Good for sheets, halyards, running backstays and control lines. Blocks are Hardkote anodized and have 17-4PH stainless headposts and shackles. Easily disassembled. Ball Bearings: Torlon Roller Bearings. Carbon-black Delrin ball bearings Sheave Size: 4" (100mm) Sheave: 6061-T6 Hardkote anodized aluminum Line Dia: 5/8" max. Cheek Material/Finish: 6061-T6 Hardkote anodized aluminum Construction: Dissimilar metals isolated for corrosion resistance. Easily disassembled Safe Working Load: 7,500lb.