The shape of the head and shank of the handle is well carved. It went into the metal head of my hammer drill with no problem. It came with wedges to expand the shank for a secure fit. The swap was so easy that my 16 year old son, who isn't mechanically inclined, was able to swap out the grips with no instructions. Pros Good fit comes with metal and wooden wedges Sturdy handle Rough finish for a good grip It totally meets my needs Cons If you want a silky smooth grip, this isn't for you unless you're willing to sand it down with fine sandpaper . The shaft is based more on round holes than on ovals. The wedges still provide a snug fit.