If these really are 316 SS, that would be impressive, if somewhat over the top. I can't test that claim without damaging one (color of incandescent sparks coming off a grinding wheel), and frankly I don't care enough to do that, because 304 SS is adequate to the task. They are definitely austenitic stainless. So let's talk form. To my surprise they're decently thick gauge and fairly rigid. I assumed the people claiming poor fit on canning jars had squeezed and deformed them, but no. Canning jars and lids have well-known standard dimensions. These fit perfectly. So now I have to suspect people are trying to put them on non-standard jars, maybe pasta sauce jars that look like canning jars, or jars with damaged threads. I don't know. The difficult removal problem is simply because these are one piece. For canning, a dome lid is pressed straight down onto the glass by a separate ring. That's absolutely necessary for canning; it avoids damaging the resilient seal while screwing it on and allows prying it straight off to use the contents. It also allows removing the band after cooling to use on another jar, and to keep it from rusting, though surprisingly few people do that. Unscrewing a vacuum-sealed lid is practically impossible (which is why pasta sauce jars with one-piece lids don't use standard threading). Well, this isn't a two-piece lid, and the gain in convenience comes at the cost of hermetic sealing. It's to be screwed down only until contact with the silicone ring. There's no advantage to tightening beyond that, and screwing it down farther means unscrewing involves pushing a long track of glass against squished silicone. People complaining that these don't seal like canning under vacuum are simply admitting that they bought the wrong kind of lid. Hermetic sealing of wide-mouth jars requires 2-piece single-use canning lids; otherwise use jars with much narrower mouths, with much less friction to overcome, and screw their lids down tight. Incidentally, the idea that the embossed branding compromises the seal is nonsense. The silicone ring fits snugly inside the lid, spanning the embossed area. Closed spaces inside the sealing ring are of zero consequence. None. And denigrating them because the silicone sealing ring absorbs pigment? I don't know what to say. The world must be a terribly disappointing place. The other style, with silicone covering the entire underside so food never touches steel, makes 316 SS even more overkill, and reduces the security of jar stacking. The ring seal of these sits in a well, which becomes a bulwark on the outside, not tall but enough to keep round jars (not squares) from sliding off. Incidentally, they do dome in the center, so if you close one on something hot, as it cools it will suck that dome down just like a canning lid. That will let you know if the seal is airtight. An airtight seal counts for little if the contents and jar weren't sterilized, but does tell you the jar wasn't sucking in airborne microbes as it cooled. Or, if it pops up, that it has done just that. I bought these for a friend, a canning jar fan, not expecting to think much of them. 316? Yeah, right. Fits like a canning band? Doubtful. Sturdy construction with a thick high-quality seal? Typical advertising exaggeration. But I have to say, they are excellent in all respects. I'm actually quite impressed; I can find no deficiency or flaw. The brushed stainless surface looks good new but I'm sure will show scratches if used as I expect these will be used, but the point is that I expect them to be used A LOT. Canning jars as long-term storage suffer a durability mismatch with normal lids. These turn canning jars into forever jars.
