220 Size 4 Blade Tail Rotor from RotorScale - RSH1011-139
NOTE: This 4-blade tail rotor is for use with the RotorScale 1104-3900Kv Brushless Tail Motor (RSH1011-138). It CANNOT be used on the 1104-5200Kv Brushless tail motor. Please check your tail motor markings for specifics on which tail motor you have.
This product is used on the following RotorScale helicopters:

220 size UH-60 Coast Guard
220 size UH-60 Black Hawk
220 size SH-60 Sea Hawk