First off, I did not purchase an aerator from this company, but rather a septic tank lid. My system is 75 years old, the old cement lid no longer fit the opening, and the opening is rectangular in shape. Besides hardware the kit basically has 3 pieces and a generous amount of high quality butyl rope. The adapter (flange) came in 4 pieces which needed to be fit together. No clue why they don’t use a single adapter which didn’t require any preliminary work. My tank is old and the concrete top is pretty ragged. It would have bee optimal to use concrete patch to achieve a level surface prior to mounting the adapter (flange). The butyl compensated for this problem to a considerable extent., but not perfectly, so the seal is certainly not water tight. The riser and riser cover are very solid, the flange a bit less so. But the main take away is that these are great guys to work with, honest friendly, helpful, trustworthy. Honestly cannot recall a better consumer experience. These guys know their stuff, and are most helpful.