xGen RX4 Evo Hardened Steel Main Shaft Fits RRP RMP RRP-037XGCompatibility: Compatible with xGen RX4 Evo, RRP RX4 (MX4 Prototype), and RRP RMP/RMX models. Fine Materials: SCM440 Steel Hardened By Heat Treatment.xGen RX4 Evo Hardened Steel Main Shaft Fits RRP RMP RRP-037XGSKU: RRP-037XG$45.00PriceQuantity*Add to Cart