Those things are indeed quite often stolen or unscrewed with a joke and distributed in the landscape: the search on a four acre meadow you can save - especially since the replacement valves are very cheap. Quality: properly - is to say: you can inflate the tire and the air stays inside. More must be a valve can not. (They really take a lot of space not away, the little things) Indispensable as a substitute for the tool bag to the saddle.
