As the TLR Race Team continues to push the envelope of performance for the 22-4, they have found themselves torn between the advantages of 10 degree and 15 degree caster blocks. We then prototyped some 12.5 degree caster blocks, and found these to have the best traits from both the 10 and 15 degree options. Now, the team just doesn't take them off ☺. This new part is used on many key TLR 22-4 setups including Ryan Maifield's 2015 Reedy Race Champion setup. Designed as a direct replacement, no other parts are needed to mount to your 22-4!