A Presta Valve is a type of valve commonly used on bicycle tires, especially in high-performance and racing bikes. It is narrower than the more common Schrader valve and features a threaded top that requires a small nut to secure it in place. This design allows for higher pressure inflation, making it ideal for road bikes. To inflate a tire with a Presta Valve, the user must first unscrew the top cap and press down to release a small amount of air, which opens the valve. Afterward, a compatible pump can be attached to inflate the tire. This valve type is often preferred for its lightweight and efficient design.