Everything you need to rebuild the top end of your 2018-2021 300RR or 300RX if you're lucky enough to have one!
Beta piston kit
Beta wrist pin bearing
Beta or Cometic top end gasket kit (choose above, see Cometic 300|250 Top End Gasket Kit for description)
Please check which size kit you need by removing the power valve cover on the left side of the cylinder (you'll find the size designation on the cylinder inside that chamber) and choose the appropriate kit above. Also, choose the Beta or Cometic top end gasket kit.
Beta 300RR (18-21) Complete Top End Rebuild Kit
Beta and/or Cometic Parts