This is the Prop and Spinner Set for the Cox Models Extra 300 EP 2.4GHz RTF. FEATURES Black nylon propellor White foam spinner Break away (pop-off) design INCLUDES: One prop and spinner assembly REQUIRES: Installation on to motor shaft SPECS Prop Diameter: 4.25" (107.95mm) Spinner Diameter: 0.87" (22mm) Spinner Height: 1.04" (26.5mm) without mounting piece COMMENTS SafeProp design: a nose in crash usually means damage, even if it is only to the prop. But SafeProp helps prevent damage. SafeProp popr off on impact, protecting itself and the rest of the plane from damage, and you can pop it right back on again. Part COXQ5808 by COX HOBBIES