When you hear someone talk about a Schrader valve, they are talking about the type of valve that is most common to bikes and cars and anything else with inflatable tires. A Schrader valve is maybe as thick as your pinky, and has the valve itself recessed inside a metal stem. The nice thing about tires with Schrader valves is that any place with airing equipment like gas stations, etc., will work to fill your tires. Most all kids' bikes and entry level adult bikes have wheels with Schrader valve tubes.
Contrast this with Presta valves, the skinnier valve used most frequently on high-pressure road bike tires.
