This is the Stock Replacement Pilot Nut for the HPI Savage .21 Truck. This nut holds the flywheel onto the crankshaft. FEATURES: Black steel construction. YOU WILL RECEIVE: (1) Pilot Nut SPECIFICATIONS: Length: 8.5mm (0.34") Thread Size: 1/4-28 cmc 11/13/02 ir/kh kr5/7/03 &