The TLR SLRC (Super Low Roll Center) Shims are made out of 100% carbon and offered in this set with two thicknesses of 0.5mm and 1.0mm. Lowering the front hinge pins allows the front end to roll more. This is extremely helpful for absorbing the extra energy caused by high bite tracks like carpet/astro turf/prepped clay. It can sometimes be counter-intuitive thinking why this helps, but a good way to picture the benefits, imagine your car has turnbuckles as front shock. When giving your car any steering input the car will immediately respond causing the rear to become unstable. This increase in roll helps slow all that reaction down.