Unscrew the tip of your Presta valve and thread on a Presta to Shrader valve adapter to easily inflate anywhere. When done, close the valve. If desired, you can keep the adapter on the valve for easy access. All the pumps we sell are compatible with either type of valve but if you have one that is not or like to inflate at gas stations, this is a useful thing to have. Our air hose out front of the shop has an adapter chained to it so it can be used with any valve. If you need help inflating your tires, just swing by and we can show you how to master any tricky valve.