NEXX Racing Arrma Grom 58mm Aluminum Oil-Filled Threaded Reservoir Shocks. Constructed from high precision CNC-machined aluminum and features a fully functioning reservoir with a realistic divider piston with a set screw for adjusting the shock rebound, an inner O-ring design to prevent leaks and a completely serviceable design that is perfect for fine-tuning your spring rate as well as dampening effect, these optional aluminum threaded oil-filled shocks are intended for the Arrma Grom platforms Provide smoother dampening action, extra tunability to your Grom and longer travel than the stock shocks! Elevate your Grom performance with these NEXX Racing aluminum shocks.