Engineered for lighter weight, these blocks are designed to handle high loads on mono and multihulls 45 ft (14 m) and up. They are constructed with mirror-polished stainless steel sideplates for corrosion resistance and lasting beauty. All sheaves are made of 6061 T-6 Hardkote-anodized aluminum for strength and durability. A lightweight, Teflon®-impregnated, composite bearing system riding on a 17-4 PH stainless steel inner race handles the primary load, while Torlon® ball bearings carry side loads.