Chromoly insert for Profile and Madera Spline Drive sprockets and spiders.
6mm for use with Spline Drive Sprockets, Galaxy Sprockets, Elite Spline Drive Sprockets, & Madera Helm Sprockets. (19mm Sprockets/Spiders can only accept 19mm insets & 22mm Sprockets/Spiders can only accept 22mm inserts. They can not be converted up or down in size.)
8mm for use with Spline Drive Spider & MTB Triple Spline Drive Spider. (19mm Sprockets/Spiders can only accept 19mm insets & 22mm Sprockets/Spiders can only accept 22mm inserts. They can not be converted up or down in size.)
