This two-pcs pack of alloy valve extenders includes a specific wrench tool for easy-fitting with accuracy. These valve extenders are extremely useful if you are using deep-section wheels/high-profile rims. They weigh almost nothing, include the key/tool needed for installation, and will outlast the wheels and tires you install them on. Each is 42mm long, which combined with the height of the original valve, is tall enough to be accessible even with deep carbon tubular wheels. 
 
NOTE: To use this superior type of extender, your tubular tire (or inner tube) must have a removable Presta valve core. If the core is fixed and can't be removed, this extender won't work (the vast majority of high-quality tubular tires and inner tubes have removable cores).