Semi Finger Tip: The Semi finger tip insert has a smooth, rounded bump close to the front edge of the insert. When properly fit, the bump rests between the first knuckle of the finger. It is designed for a more relaxed grip and ideal for bowlers who suffer from arthritis or have weak grip pressure. Power Nub: The finger pad of the Power Nub is lined with rows of small, raised bumps. The Power Nub has a very sharp feel and is not for the faint of grip! This style is recommend for a strong grip.