2.5" / 2.5" Inch 4 Bolts to 2.5" V Band Turbo Adaptor (Cast) Extremely Strong Casting 2.5" 4 bolt to 2.5" V-band conversion flange turbo adaptor (CAST) -Extremely strong casting -2.5" inner center on 4 bolt side -2.5" V-band side Can be also used as a 2.5" V-band to 2.5" 4 bolt adaptor