●Use for T-REX 500.●Must with:500 Four Blades Main Rotor Head assembly (H50145).●Feathering shaft x 4(Φ10xΦ7.9x35mm)●Feathering shaft washer x 4(Φ3xΦ10x1mm)●Washer x 4(Φ6.1xΦ10.5x0.4mm)●Socket screw x 4(M3x10mm)