This gasket is for a 1/10 RC car shock that comes stock with Deerc or Holyton cars. For example, here is the link to the holyton car that I installed this on. I've also included a photo of the shocks themselves. The gasket is 11mm in diameter and is not flat.
After you clean the shocks and add oil, you add the gasket, cap it and twist the top of the shock closed.
11mm_1-10_rc_shock_gasket_3_layers_merged.stl | 28.8KB |