If you keg beer, you may have seen these old type of relief valves commonly called "dome valves". What do you do if they start to leak? They are made of plastic and have an internal mechanism that is sealed and cannot be replaced. You got to replace the entire dome. Fine. However, they are no longer made, and any replacement you can find are as old as the one you have. So what do you do? You can buy a replacement lid for twenty bucks (used) to about $40 new. Sorry, I'll just add another $10 bucks to that and buy a keg off Craig's list. You can have a fitting welded on to accept the newer valve. Also costly. Got to be another way. So I Looked around and found these weldless valve replacements, that allow a standard relief valve to be used in this type of lid. I paid $11 dollars plus shipping from Keg Connection, but now I find them in Northern Brewer for under $5. http://www.northernbrewer.com/shop/keg- ... style.html The only down fall I can see is that they are made of aluminum, not stainless, so it might not work well for wine or cider (the acidic nature could damage them, I suppose), but for beer It should work fine. Two rubber O rings (one for the lid seal, the other to seal the threads) will eventually need replacing, but O rings are cheap. I have replaced the domes on two of my kegs and they seal up tight.