MagiDeal 5pcs Bicycle Presta Wheel Rims Tyre Stem Air Valve Caps Dust Cover - Blue. Prevent leakage, dirt and rain water to extend the service life of bike tires. Upgrade your plastic caps with some style. It makes the bike look more attractive and special. Direct replacement, no modification needed. Easy to install, only use the wrench to put the caps on to the tire valve stem.