I put these on all my tires, both cycle and bike, as they give me easy access to the valve stem head should I need it. They're stronger than the plastic versions that come with some of my inner tubes and have a rubber gasket to assure a tight seal. And they're inexpensive too
I bought one of these for every bike I own, and I always hand one to each person I do a dual sport trip with. They're perfect for quickly deflating tubes to pack down, or for packing a spare tube as small as you can before a ride.
$0.39 is 100% worth the time you'll save fiddling with a tube without one of these.
This is one of those little things that you pass by because you never think you would need it. It is so worth the money to have this little gem on hand when you do need it. Don't waste your time with the little plastic ones.
I bought several of these and I put one on the back wheel of all of my bikes. I also gave some to my friends. So far I have needed it exactly one time when my valve core wouldn't seal properly after i aired down in the desert, if you screw these down properly they are airtight. Sometimes I also use these to remove valve cores when changing tires if I cant find my other valve core tool because my garage is messy.
The cap is fairly thin...the picture makes it look beefy but it's not. Works great though. I have one on each bike so I can always change a tube. My buddy stole my 'real' tube tool with a bleeder, core remover, and stem puller and I haven't replaced it yet because these suffice.