I got them because it is very difficult to keep the tire inflated on my car. When the pressure is low, for example at the end of winter, when you attach the air pump, the valve stem wants to get into the hole in the rim, and pumping it up is a chore. I thought these extensions would make things easier, but they were tricky to install, never seated properly on the inner tube valve stem and would not let air through. Couldn't use them successfully with an air pump. So at least for that purpose Iโฆ