Nexx Racing Arrma Grom 58mm Aluminum Oil Filled Threaded Damper Shocks. Constructed from high precision CNC-machined aluminum with an inner O-ring design to prevent oil leaks and threaded bodies allowing you to fine tune your spring rate, these optional aluminum threaded oil-filled shocks are intended for the Arrma Grom platforms to provide supreme smooth damping action and extra tunability as an ultimate performance upgrade.