This is the APC 9X6 Sport RC Plane Propeller 

Sport
Use LPAR06E adapter rings (not included)

Pitch (inches): 6
Propeller Diameter (in.): 9
Hub Diameter: 0.80 in.
Hub Thickness: 0.47 in.
Shaft Diameter: 1/4 in.
Product Weight: 0.78 oz.
Color: GREY