The Seismic Cassette Hub utilizes a new internal mechanism, which Eclat's been working on for the past few years called TCS (Toothed Coupling System). Inspired by systems used on high-end road and mountain bikes, re-designed to work inside a BMX cassette hub with a 14mm axle and a 9t driver, something which was never possible until now. Instead of the typical pawl based cassette hub, the Seismic hub uses x2 coupled toothed ratchet rings, which are inside the hub and the driver. The two rings are pushed together with a very special design of spring, which allows the hub to transfer power in one direction, and ‚Äúfreewheel‚Äù in the other. In a nutshell, it‚Äôs a much stronger internal mechanism, which can‚Äôt fail even after years of heavy use. No more skipping, slipping or popping, you can really crank this thing as hard you want and it‚Äôs not going to fail. Even after years of heavy use, this hub was designed to keep going on and on.