I can't remember what this device is called. I saw it at a bike shop out of town and am looking to buy one. It was a small, weighted device that you could keep attached to your valve stem and as your wheel rotated, gravity and the device would pump small amounts of air into your tire, thus keeping it inflated.
I want this for a wheelchair tire that has a presta valve. I also have an adapter on the stem for standard pumps. Really I just need to know what it is called so I can find them at some etailers. I've searched high and low and I can't seem to find the right terms.