Bought to fix 2 old bike pumps. Both had the same problem: the nozzle was no longer fixed on the valve stem due to the rubber drying out. They use a sharp little "blade" to hold the threads and have a soft rubber seal inside to prevent leakage. I'm not sure how long they stay soft, but they can be replaced and seem to be quite strong. The included worm gear clamps are a nice touch, but you could cut yourself if you don't bend them tight. (This is a design limitation of the clamp, not the item itself, so no complaints). All in all I recommend them. Installation Note: If your bike pump hose is too stiff/small to fit over the hose burr, use a dab of dish soap to lubricate it. Be careful not to injure yourself on the handle. Can't comment on longevity, but as far as initial function goes, they work great.