It's not a Reynolds one? https://reynoldscycling.com/products/reynolds-valve-extenders
If so it's just screwed on. If you can't pump up the valve may be stuck closed.
@hazzelfrazzel started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
It's not a Reynolds one? https://reynoldscycling.com/products/reynolds-valve-extenders
If so it's just screwed on. If you can't pump up the valve may be stuck closed.