Uses: bicycle chain, magic buckle, chain connector. Quantity: 2pcs. Included: 1 x Pair of Bicycle Ch ain Links. Gross Weight: 3g. The two latter numbers on it stand for chain width. Product size: 8 speed (6 \ 7 \ 8 universal): 20 x 7.1 x 5mm/0.79 x 0.28 x 0.20".