Very nice to be able to fill tires without having to hold the fill valve on the tire stem. Make sure you have room to lock it in place as I had very little leeway on my tires. but got it to workNo check valve…as soon as it is “locked” you better have positive pressure flowing or it will deflate your tireMy Ryobi battery powered inflators each started leaking air around the hose at the chuck end, so I ordered a Shraeder barb end adapter here on Amazon to let me use these locking air hose chucks on the two Ryobis.Installing the shraeder barb end adapters in the Ryobi hoses was not a problem, and these hose chucks screwed on without any problem. I was impressed with the construction on these: The Ryobi chucks consist of thin plastic levers secured in a stamped and crimped sheet metal shell, with a plastic barb attaching the chuck to the hose, all held in place by a small screw in the thin sheet metal - flimsy at best, with a lot of rattle and slop in the chuck mechanism .These adapters use a metal barb and sturdy metal lever, and the shell is metal about 3x greater wall thickness than the Ryobi part, A shouldered pin inserts through the lever and can only be removed by compressing the lever down into the shell with a LOT of effort.Which is where the question comes in. The Ryobi uses a black rubber part for sealing the chuck around the tire valve. This part abrades on the valve thread, and eventually the part (or entire chuck) needs replacement.The 'rubber' part on these chucks is grey, and looks more like silicon than rubber. And while it makes an adequate seal around the stem, it seems to leak a small amount of air when attached to the tire stem.This leakage is a slight hissing sound, and probably not a problem for car and truck tires, etc. But I use my Ryobis for topping up the latex tubes on my TRI bike just before the start, and small hiss sound coming from a high pressure small volume tube means an unacceptable loss of pressure. The old Ryobi chuck - cheaply made -did not have any hiss and removed with a sharp popping sound. This chuck is less secure. I had always been able to avoid buying a $50+ pro presta valve chuck to inflate my tires, but may need to bite the bullet if I can't get these working better. I will try taking the chuck apart and seeing if the black rubber seal from the Ryobi will work in the new chuck, but question why the grey component in this chuck leaks air, when the really cheap chuck on the ryobi didn't leak. And if it has a small leak now, what will it be like after a few months of use every other day?Again, this is very well made and heavy duty for most purposes - including most bike tire use. But for my fringe use of latex tubes and racing tires, this doesn't work as well as the cheap Ryobi chuck - go figure!!!So these are well made chucks and probably perfect for most uses, but not for my application.EDIT: There were two of these extensions in the package, and I found that the seconfd one didn't leak at all. So I played around with the leaky one, taking the chuck apart and removing the silicon/rubber seal that goes around the valve stem. I saw a small irregularity on the surface, a bit of rubber protruding out. removing this irregularity fixed the problem, and thyey both work perfectly for me.WORKSOn my inflator air hoses you always have to screw the cap end onto the tire valve, which is hard to do with my motorcycle tires, and I lose air while unscrewing the cap after an inflation. This tool screws onto my air hose cap and I can then just clamp the air hose over the tire valve.I only gave it 3 stars because I had a hassle connecting it to the hose on my air Compressor, once I got it in it works perfectly.I use it on my Fanttik X8 inflator. It has screw on connector to the tire valve. Takes to long to do that if you are doing multiple tire. I prefer the locking air chuckk end connectors. So, you just connect these to the end of the screw on connector. Then you have the locking air chuck connector on the end and the hose is now longer.My Dewalt 20V inflator only had one thing I hated. Screwing the air fill hose on and off sucked especially in crappy cold weather. Being able to clamp the hose on in a fraction of a second… priceless. Highly recommend for the money!