Stan's NoTubes 55mm Aluminum 2 piece valve.

Stan's NoTubes black valves are made of super-lightweight aluminum and are half the weight of standard brass valves. They are compatible with most rims designed for the tubeless system and fit perfectly on all Stan's NoTubes rims with BST technology. If you want to add some fluid, you don't have to remove the tire from the rim. The vents have a removable replaceable cartridge, which will allow you to conveniently add fluid using a dedicated Stan's NoTubes syringe.