The Dunlop valve, (also called a Woods valve, an English valve or a Blitz valve[1]) is a type of pneumatic valve stem in use—mostly on inner tubes of bicycles—in many countries, including Japan,[2] Korea, India, Pakistan, Sri Lanka, most European countries, and a number of developing countries.
[4] The inner mechanism of the valve can be replaced easily, without the need for special tools.
The Dunlop valve originally used a tight rubber sleeve (see illustration of "original plug") which had to be forced open by air pressure while pumping (not only were these difficult to inflate, but the rubber would perish over time, allowing leakage and eventually, complete failure), but modern Dunlop valves use a different plug (core) using either an internal ball bearing or a spring-loaded rubber plug that is unseated by pumping, making the valve as easy to pump as a Presta valve.
It superseded Dunlop's original valve for pneumatic tyres.
The external thread of a Dunlop valve is 0.305-32 TPI (approx.