Norestar Boat Anchor Chain Stopper/Lock for 5/16 inch to 3/8 inch Chain, Anchoring Prevent unnecessary strain on your windlass by securing the chain to a chain stopper Handles chain from 5/16&quot; to 3/8&quot; Pawl flips up when not in use Constructed from solid stainless steel Base Measures 3-1/8&quot; x 2-11/16&quot;