Thanks for the feedback guys! My goal was something for the airsoft community that is simple, cheap and readily available! :)

I Thought that i would try these out, I am pleased that i did. I had an uneasy feeling that the mags wouldn't fill with liquid propane unless propane gas could get out (of the mags during the filling process). That was wrong thinking- I'm convinced when you pressurize (fill) your mag with liquid propane gas any gas that was left in the mag would be compressed as well. I put the O-rings in a mag (the longest part is getting the little baggie open) and it worked exactly as advertised- No propane spraying out on my hands, no noise, no smell. Since I have a condition called essential tremor (shaky hands) I hated drawing attention to myself while filling my mags and now i won't. There's no way that Sequential is getting rich selling these things- He's helping out fellow airsofters. BTW I installed mine into Hicapa mags

+1 for these o rings! It's amazing how a small piece of rubber can make such a difference (why don't manufacturers include this?!). Very easy to install, cheap, and saves a lot of gas. Anyone with a GBB gun should get these. I also really appreciate the note with instructions (not that you would need it) and helpful reminders. Thanks Sequential!

I installed the o-rings to all my TM mags yesterday and it did work. No more hissing sound while filling the mag :D

Thanks Sequential !!!

Thanks for all the kind words guys! I am glad the o-rings were put to good use! :D

I grabbed these O-rings to add to my WE XDM magazines (there were no rings present). Initially I was concerned that the O-rings may fall out but they fit very snugly. After prodding them into place with tweezers I found the best way to seat them was using a gas fill adapter but being careful not to pinch the O-rings on the edge of the valve's conical inlet.

After installation, filling the mags was silent with no leakage. With a silent fill I was confident that I was completely filling the mags as I could actually hear when the gas stopped flowing (ie. pressure equalized)!

What can I say besides 4 thumbs up for these O-rings!

Yeah I don't know why manufacturers would sell gas mags without the o-rings... I have seen a few places that sell the black rubber ones, but not for any cheaper than these, and the red color makes it easier to reassure yourself that they're still there.

Thanks for the review dan! Yup the best technique was to use the gas fill adapter to gentle tuck them in. The tweezer method sometimes is too rough. :)

Do they work in the larger gas mags for example kjw m700 gas mags? Lol I run Co2 for all my pistols.

Not quite sure because I don't have a M700 to experiment with but if you send me a picture of the fill-valve in PM I can see if it works.

How would one know when the magazine is full?

When the bottle of propane stops hissing.

* There once was a message, but now gone. Anything else you read about this is heresy :smack: *

Yes, they fit TM PISTOL mags. Not sure about anything else. Also, I'm guessing you didn't follow instructions given to simply put them on the valve and push them in place with your adapter.

*boom*