There is a trim ring that sits between the faucet and the countertop that is made of cheap plastic rather than brass and it shattered as the plumber turned the wing nut that tightens down the faucet. The instructions do say "do not overtighten," but if the part were made of metal, this warning would not be necessary and a tight seal to the countertop could be achieved. I called Isinkerator, got through easily, and the rep sent me a replacement trim ring right away, but now the plumber has to come back to install it. As it stands, you cant tighten the wingnut enough to keep the faucet from swiveling without breaking the trim ring.