Use as sheet control blocks on dinghies, or for control lines on larger boats. High-impact Delrin sheaves turn on polished stainless steel spacers, so the cheeks won't squeeze or bind the sheave, even under extremely heavy loads. Head shackles are stamped stainless steel with clevis pin and cotter ring. Cheeks are black hard-coated anodized aluminum. Straps, headclips, shackles, and rivets are tumbled and polished stainless steel. Sheave: Delrin Cheek Material/Finish: Aluminum