Alloy Presta Valve Extension, Hex Key Fiiting, Non-Slip pump fittingThe simple way to ensure that you don't get caught without a spare inner tube for your deep section Aero rims.These simple but functional lightweight retro-fit adaptors will convert a standard length Presta Valve into a usable XL valve.The clever Woodman designed exterior profile allows for most press-on high pressure pumps to inflate without slippage.Simple to fit:Threads onto standard type Presta valve as a normal valve cap would do, and features an internal hex-key recess to fully tighten..To install, release the knurled Presta valve lock 2/3s of the way along it's spindle - as you normally would to be ready for a pump to be used, and install the extensions onto the valve..(Existing air pressure will naturally keep the valve closed and air tight - as it does with other types of valve - and pump pressure will open the valve to inflate.).Features:Lightweight, precision CNC alloy.,Anodised Black or Red finish,Size options: 48mm or 72mm..