Stan's Threaded Valve Extenders let you convert deep-section rims to tubeless. They're precision-machined from aluminum and are designed to fit deep-dish carbon and aluminum rims. And, they're threaded on the outside so you can install the Presta lock-ring nut for a perfect seal.
Removable valve cores sold separately
Mountain Bike Tire Installation on Stan's Tubeless Wheels - Stan's NOTUBES