Economy Chain Stopper f/5/16", 3/8", 8mm & 10mm ChainChain stoppers hold the chain and take the load off the windlass. They are used to set and ride on the anchor, break free the anchor or to prevent accidental free fall of the anchor while under way. Also recommended for VW series rope and chain systems to hold the chain while changing over from rope to chain.8/10mm (5/16"/3/8"): B - 62mm (2-3/8") C - 6mm (1/4") F - 80mm (3-1/8") G - 46mm (1-4/4") G1 - 17mm (5/8") I - 92mm (3-5/8") J - N/A J1 - 37mm (1-1/2") K - 74mm (2-7/8") L - N/A M - M10 Owner&';s Manual (pdf)Brochure (pdf)