Great Planes 2-1/2" Aluminum Spinner FEATURES: Machined For Accuracy, Then Polished To A Gleaming Finish; Easy To Install, Having A Bolt-On Design, Centers Each Spinner Perfectly On Its B INCLUDES: One Aluminum Spinner Cone One Aluminum Backplate (See Specs For Sizes) One 10-32 x 1-1/2 Mounting Bolt One Box with Installation Instructio REQUIRES: One Spinner Adapter Kit (See COMMENTS)