Instruction: Use for T-REX 450 Pro. Specification: Metal main rotor housing set x 1 Pin x 2(Φ1.5x18.7) Damper rubber x 2(Φ4xΦ6.5x4) Aluminum collar x 2(Φ4xΦ5.6x1) Socket screw x 1(M2x10) M2 nut x 1