Buku Speed Tune clutch
The Buku Speed Tune clutch is the world’s first and only clutch for nitro RC vehicles that lets you independently tune the spring tension for each shoe without removing the motor or clutch bell. There is no need any more for pulling out the engine, breaking down your clutch, and picking a spring for each shoe. Each clutch shoe is equipped with a special Aramid fibre pad that is extremely wear resistant and that causes virtually no wear to the clutch bell. The extremely low wear rate and uniform friction characteristics of the Komposite fibre pads with no wear to the clutch bell create a very consistent and reliably performing clutch.
Source: Buku [bukupower.com]