Package of 12 Black Ferrules for use on Iron shafts. Dimensions .370" x .530" x .625" Length Bohning manufactures high quality ferrules for use in Golf Club Building and Golf Club Repair. All Bohning ferrules have a 20 degree countersink in the bottom inside diameter to allow a cushion of epoxy to form, preventing shaft breakage. Bohning Golf ferrules are manufactured in Lake City, Michigan.