Yep. the extra shim is indeed the retainer to prevent your chosen squat shim from sliding out should anyhting come loose etc. You will all be pleased to know that we are now offering this "shim" as a seperate part too should any one lose or break one. Also bear in mind that "some" combinations of anti squat can be achieved by adding two smaller shims together should lose/misplace any.
The full range of "DMS X Partz" will be hitting the X-Factory UK site (
www.xfactoryrc.co.uk) and are already on our shop site too.....