This is direct drive diff lock rings for Yokomo and Team Associated 1/12th scale pan cars. The composite rings allow to convert a ball differential into a spool axle, a setup that is very popular when running on high to very high bite surfaces such as CRC black carpet. The rings are run instead of the diff plates and ball and they interlock with the spur gear, making for a solid axle with no differential action. The plates are available for Yokomo kits, fitting the YRX-12 and YR-10F cars, and they also come as Team Associated compatible variant.