They allow you to keep the valve stem caps visible to the footman who wants to AIR your tires that you have nitrogen. If he/she knows what N2. Wears a hoop with a slight touch of class. Good for carving where they don't come loose every 100 miles. I've built two trucks (4 each) and my scooter and I have eight left for another car or for a friend using N2. Worth the extra dollars and if one gets stolen you have a spare.