Stainless steel block at an unbeatable price with hollow center for more lightness and more strength since the load is spread on a large area of the sheave and the flanges. Ball bearings, anodized aluminum sheaves with 316 polished stainless steel body and 304 stainless steel fittings. Breaking load is twice the working load. Rope: 3/8''. Working load: 1150 lb. Sheave diam: 1.75''