Required to access the internal stems of dual valves. But I couldn't put them on while the tires were up. Everything would be fine if there were no wheels/tires on the car. Shame as they were at a great price and were badly needed.
Pros
EXCELLENT QUALITY: The tire valve extender is made of brass, chrome plated on the surface, and comes with a metal dust cap, will not rust or erode, strong and durable.