We have a small faucet at our kitchen sink used only for instant hot water. Can not find a brand name on it anywhere. A short while ago, whatever the aerator set up was must have fallen out. I was able to recover 2 flat aerator screens that are 7/16" in diameter, as well as a metal piece thats about 1/8" tall and shaped like an asterisk *. The dispenser on the faucet has an opening that is 7/16" (possibly thinly threaded? hard to tell). and the outside measurement is 11/16" in diameter. I can't twist it off by hand or even with the force of a curved pliers, so not entirely sure it comes off. Any idea what I can use on this that would work as an aerator?