teah tabz is right mine has two bolts opposite each other screwing down onto the flange and a 3rd screw at the top that seems to do sod all.the thing is with this housing the flange does not go any slimmer at the top for the hose to connect to.and the restrictor is way too small for a t34 hose to connect to.from tis i think that the comp housing has been modded in some way.surely there must be a way round this as i dont want to restrict the car.any more advice people?