Good quality. Very rigid and heavily reinforced with ribs.
I replaced two saggy lids with these heavy duty 24" lids and I think the lids will hold up well. However, the sales sheet said stainless steel screws were included. I received no screws. Installation notes for others: Unlike many standard flat lids, this lid extends over 2" down into the riser. This is good because the lid fits snugly and can't slide off, even unfastened. On the other hand, in my pump tank, I had to trim the top of the float tree and the tube that contains the UV light, so they didn't interfere with the lid..