Maxwell Chain Stopper f/3/8" or 10mm Chain Levered. 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. 10mm (3/8"): B - 86mm (3-7/16") C - 20mm (7/8") F - 190mm (7-1/2") G - 130mm (5-1/8") G1 - 30mm (1-3/16") I - 86mm (3-1/2") J - 44mm (1-3/4") J1 - 10mm (7/16") K - 64mm (2-5/8") L - 95mm (3-3/4") M - M10 Specifications for Maxwell Levered Chain Stopper f/3/8" or 10mm Chain: Manufacturer: Maxwell Color: Black Package Contents: Maxwell Levered Chain Stopper f/3/8" or 10mm Chain Maxwell P104373: Chain Stopper f/3/8" or 10mm Chain Levered