Dellorto Billet velocity stack that fits VHB 27,29,30mm carbs. Stacks are nicely polished and measure 70mm long and 50mm at the widest part. Velocity stacks are bored to match carb size and not a one size fits all application. Please select the velocity stack size you need from the pull down menu. NOTE: Stacks only fit Dellorto VHB and will not fit on Mikuni, Kehin, Amal, Bing, S&S or other brands of carbs.