MRP Thunder Tower Shift Knob, Material: Aluminium, Color: Silver Color Rings available. Upgrade your buggy with the best CNC polished alumnimum upgrades available on the market made by the brand you trust MRP, the number one accessories companies in the buggy market. Available in both 10mm and 12mm make sure to specify the one you need. 10mm works on Carter 150/250/300 Karts, Lance / BMS 150 / 250cc 10mm versions. 12mm works on High Rev, Hammerhead, Kinroad, and more. Make sure to measure before ordering race shifter knob.