The Shimano Dura-Ace 7600 Track Cog comes in four options for teeth count ranging between 13T and 16T in 1/2" X 1/8". They are CNC machined to ensure a reliable chain line, limiting unwanted tension on the chain. Their chromoly construction gives an additional level of durability so that you won’t be wearing either your sprocket or your chain too hard even after months of power training. Chromoly steel has an excellent strength to weight ratio and is considerably stronger than standard steel.
Meant for serious use on the track, the Shimano Dura-Ace 7600 Track Cog is designed for use with the Dura-Ace track hubs and most other common hubs. The cogs have a right-handed threading of 1.37" x 24 TPI. You can use these cogs with the added confidence that the Dura-Ace marker guarantees the high quality and reliability, which you expect from all top-end Shimano parts.