This is a set of two Kyosho 65.5mm Universal Swing Shafts, and are intended for use with the Kyosho RB5 SP. Kyosho universal swing shafts (CVDs) are made from durable, high quality hardened steel. The bones measure 62.5mm from the outdrive pin to the CVD pin. These CVDs come stock with the Ultima RB5 SP Kit, but are also required for use with the middle suspension arm conversion using KYOUM521 rear arms and KYOUM519 hubs with the standard RB5 or Lazer ZX5.