Genuine Black Cat Interior Bike Tubes for MTB And Racer Bikes
Schrader/ AV:
This is wider than a Presta valve and typically the same circumference from top to bottom. The outer wall is threaded so a cap or pump head can be inserted. The pin in the center is a spring-loaded check valve that controls airflow and pops as you unlock it. Check valves are meant to allow airflow in only one direction; your Schrader-valve tube requires pressure on the inner pin to let air in.