This review is directed to knuckleheads like myself who know very little about the tires of the cars they drive. In fact, if you are like me, you know equally little about any other parts of your car. My review is intended to caution you not to purchase this product if you are not sure that you need it. If the valve stems on the tires of your car are easily accessible, as is the case with my car, this connector is worse than useless: if you tried to use it, you would just be impeding the process of quickly and efficiently filling up your tires. This Topeak connector appears to be designed exclusively for bicycles and motorcyles. There are certain Amazon reviewers who state without qualification that the benefits of this connector extend to cars. I want to caution you that any such benefits would be limited to those cars whose tires do not have easily accessible valve stems. You may wonder why I purchased this connector in the first place, when I could have readily foreseen its inapplicability to my car. After all, under Product Features the following language appears on Amazon: "Essential for air spring forks and shocks and the hard to reach valves on 12" and 14" wheels." TThe answer is that I made this purchase in the mistaken belief that the Topeak connector had a quick-release pull/push feature on the end that connects to the tire valve stem, rather the typical threading feature, and that this would enable me to expedite the task of connecting and disconnecting my air compressor in successive relation to my four tires. When I made this purchase I did not know, and indeed I still do not know, the difference between an air spring fork and a plate of spaghetti. Nor have I ever, at least until now, seriously considered the size of my wheels (to calculate a tire's unloaded diameter, after all, all you have to do is multiply the tire's width by its aspect ratio to get the height of the tire, then add twice the tire's height to its rim diameter: how could I not have known this all along, indeed since the hour of my birth?). Furthermore, even if I had been carefully reading the Topeak's product features, the word "essential" would not have deterred me from purchasing it: purely as a logical matter, the fact that a product is essential for one purpose does not necessarily render it useless for another. If anyone from Todson, Inc., the company that manufactures this device, happens to be reading this review, I believe you would be doing the public a great service if you were to revise your product's description to make its inapplicability, and not just its applicability, easier to comprehend. The original version of this review was written in August of 2009, 2 and 1/2 years ago. It has since drawn a lot of commentary, some of it favorable, some of it highly critical. Judging by their ire, some of these critical reviewers seem to be on the verge of having an apopleptic, perhaps even apocalyptic, fit. Out of an abundance of concern for their well-being, and last but not least my own, and in all fairness to this Topeak connector, which is well made and which I'm sure can be very useful for its intended purpose, I am hereby revising my intial review. I am also increasing the products's star rating, from two stars to four stars (deducting one star from the maximum rating of five because I believe the product's description needs clarification).