On my PO 45mm ETA from Andrew, the HE valve unscrews. It consists of crown tube, crown, crown stem, tension spring, & stem gasket. mine was missing the crown gasket which fits up inside the crown. I believe the crown gasket is the most important one for keeping moisture out. Can someone confirm this? BTW adding the crown gasket wasn't too hard. BTW don't play with it too much as it will unscrew from the stem and fall off! At least mine did.