FUSION BLACK TURBO PRO 4" 4" Comparable to the current industry black turbo in durometer bur will not leave marks. Recommended for PFF, & soft hard coatings. FUSION BLACK TURBO PRO 3 1/2" 3 1/2" Comparable to the current industry black turbo in durometer bur will not leave marks. Recommended for PFF, & soft hard coatings.