This is a set of optional Kyosho Middle Suspension Arms, and are intended for use with the Kyosho Ultima RB5 SP. This set includes one front suspension arm, and one rear suspension arm. This suspension arm set is also used as a tuning option with the Lazer ZX5 and the Ultima RB5 but the SP KYOUM519 hubs and KYOUM522 drive shafts are required.