Looking for a unique and high quality BOV (Blow-off Valve) This BOV is built to withstand the toughest conditions. This BOV is not like any other BOV on the market. This is a complete seal BOV. You can hook a vacuum pump up to it and it will hold the BOV open until you let the vacuum go. we use a very light spring because of how well it seals. this makes it blow off when the time is right to keep the turbo lit and keep your throttle response quick and reactive like you want!