Blade Main Rotor Blade Mounting Screw&Nut (2): 300 X BLH4503 is compatible with¶ôǨBLH1500,¶ôǨBLH1550,¶ôǨBLH1580,¶ôǨBLH4480,¶ôǨBLH4580,¶ôǨBLH4650