The Presta valve has an interior system, a valve cap, and an outer stem. What's more, it has a lock nut which takes advantage of to safe the stem on the wheel rim. The air pumping technique of this valve is a bit tricky due to the small valve diameter. https://nowbookmarks.com/story19769646/how-much-you-need-to-expect-you-ll-pay-for-a-good-live-chat-support-prestashop