EAI Superstar Sprocket: 

The EAI Superstar cog's foundation comes from professional level track racing. The design of these cogs is based on close cooperation with the highest level athletes in the small cult world of professional track racing.

Euro Asia Imports has been manufacturing one of the best sprockets available in the market. Supreme quality with finely CNC finished edges made from the strongest steel available, no wonder even the pros use them.