The stopper fits nicely but all of theses lids don't fit exactly and the O-ring doesn't fit the groove.

Mostly it’s pretty good, but I have several critiques.1. I was disappointed that it did not include an O-ring. The description on the website should make this clear.2. It seemed to be even harder (i.e. nearly impossible) than with the original lid to get an O-ring to seat into the groove. Is the diameter of the groove just slightly smaller, maybe by a fourth of a millimeter? It would be good if an O-ring were included and were already seated, as evidence that it is possible to seat one.3. There is now a small lip around the center hole, which seems like a good improvement. It sealed against the stopper easily and was airtight. In the original lid, in a couple of cases, I found that there was a small gap between lid and stopper, apparently due to the hole not being perfectly circular, and I was able to correct it with some fine sandpaper. The gap allowed CO2 to escape without bubbling through the airlock.4. One of my original lids developed a small crack in the top, just above one of the vertical ribs, which is the reason I ordered a replacement. It does not appear that this area has been strengthened or reinforced.So, overall, I’d say it is an improvement, but would benefit from further improvement.

Always nice to have a spare.

the carboy needs to be maybe 3mm thicker as there is tendency to buckle. Must exercise extra care. The Spigot does what I expect it to. Overall design could be more balanced especially the blo molding of carboy.

If you overtighten (and you will), you will get hairline cracks on the top perimeter. You should always have a couple spares lying around.

Fits well...perfect fast delivery

Bought a new one to replace my old one that lasted for about 2-3 years

The accompanying o-ring doesn’t fit securely inside the lid. Was able to get it to stay in there with a little keg lube, but wouldn’t stay in otherwise.

First lid got a crack right over where the threads and gasket are so this is a replacement. Ordered an extra just in case my other one cracked and sure enough pulled it out this weekend and it was cracked in similiar fashion and spot so good thing I ordered two.These lids do seem thicker also then the originals I had so hopefully they hold up better.

Don’t tighten too much as the lid will crack snug is all that’s needed to seal

I bought two Fermonsters and after about 15 batches, one of the lids cracked and is now unusable. It loses one star for that.As far as folks having issues with the rubber stopper not staying put, you need to dry the stopper and the opening of the lid. If those are both clean and dry, the stopper sticks very well.The o-ring is another issue for some folks, but I just leave mine in place. I always soak the lid in sanitizer before using, and I just leave that o-ring in place. Even after kegging a batch, I remove the lid, keep the o-ring in place, rinse it off well with warm/hot soapy water, then soak it in sanitizer (since I already have a batch mixed up if I'm kegging), then air dry and store it.It's a pretty good lid, just wish mine hadn't cracked.

For those having issues try the buon vino stoppers much better than others never had any problems with those