The B4 features super-durable, high-grip seat material to keep you in place, and heavy-duty DuraTech ballistic nylon reinforcements to prevent knee brace wear. The seat includes raised O.E.M. logos, just like the TC4. Track-tested by the FX race teams, the B4 is the pro riders seat cover of choice. Toughest seat cover on the market. Heavy-duty grip pattern material. Ballistic reinforced knee area. Optional Bump for increased control (sold separately).