This is an APC 22x10E Electric Propeller. FEATURES: Composite propeller construction Thin propeller ONLY designed for Electric use INCLUDES: One APC 22x10E Electric propeller SPECS: Hole diameter: 1/4" Propeller diameter: 22" Propeller pitch 10 COMMENTS: The propeller comes with five locating rings: .128 .158 .197 .237 .313 The locating ring combines with the hub to create a precision fit. rmb 01-03-07 ir/jxs