Scotty #102-BK Strongback Oar Lock  (1 Pair Per Pack) Strongback Oar lock has a 1/2 inch straight shank, molded nylon over stainless steel core 2 1/8 inch inside dimension, 1/2 inch straight shank Low friction nylon creates smooth and quiet operation Competitively priced against standard galvanized and bronze metals,2 1/8 inch inside dimension for standard oars