Individual Shimano sprockets for Shimano cassettes. 7, 8 or 9 speed compatible. The differences in thickness between 7-, 8- & 9-speed sprockets that don't have built-in spacers are so small that substituting 2 or 3 in a cassette won't have any affect on the indexing.
These cogs, made by Miche in Italy, are very high quality and work exactly the same as Shimano's cogs. They are available in more sizes than Shimano's. They are also available for Campagnolo cassettes.