This is a replacement Kyosho Aluminum Rear/Inner Suspension Holder, and is intended for use with the Kyosho Lazer ZX5 FS2 SP. This suspension holder uses inserts to adjust the rear anti-squat settings, simplifying setup changes. A complete set of inserts are included. This is also an excellent upgrade part for the rest of the ZX5 family when a more durable suspension holder is needed.