In a world where nothing is standard, enter valves on bicycle tubes. Presta (french valves) are long and skinny with a nut at the top you have to unscrew to inflate the tube. They are found on road bikes and high end mountain bikes, and used for running tires tubeless (more on that at a later date). Schrader valves are the most common found on car tires, kids bikes, lower price point mountain bikes, hybrids, and department store bikes. Here's a handy graphic to give you the nuts and bolts And check out the videos below for guidance on how to inflate a tube with either valve.