SAILING BLOCK: Made of stainless steel and nylon, these blocks are rust-proof and wear-resistant. SINGLE BLOCK: Pulley wheel with ring tip and stable rotating and connection, you can use it with peace of mind. SAILING BLOCK: Mainly applied in boats, fitness boats, hunting, boating, store, and more uses. SAILING BLOCK NYLON BLOCK: Pulley wheel with ring tip and stable rotating and connection, you can use it with peace of mind. SAILING BLOCK ACCESSORIES: High load plain bearing, stable working performance, bring you much convenience.