Yokomo YZ-S4C O-ring Cap (4pcs.) for YZ-870C/YZ-834B 橫崛 Yokomo YZ-870C  [YZ-S4C]

That's a resin O-ring limitation to your lower component about the shock cylinder, that's to be an ordinary component the YZ-870c. Contains 4 pieces.

Supported Chassis
YZ-870C