4 Bolt to 3.00" V Band Turbo Adaptor (Vice Versa) Turbo Exhaust Downpipe 2.5" 4 bolt to 3" v band conversion flange turbo adaptor -CNC machined from stainless steel -2.5" inner center on 4 bolt side -2.5" inner center on v band side -3" outside diameter v band flange ( must be use with 3" v band clamp and adaptor) can also use it as 3" v band to 4 bolt adaptor