I cannot say for sure because I do not have a ro/di of my own at this time, however I have done quite a bit of plumbing and also know that the ro/di were first designed for drinking water and specifically to be able to retrofit your home water lines to accept them. All that said, to the point that i would expect you should be able to visit and well stocked hardware store and find the adapter you need. Your best bet will be to remove the airator from the faucet you wish to connect to, and if possible the piece of your ro/di unit that you need to connect to and bring them both to the store. If your hardware stores are anything like mine the guy will probably do all of the matching work for you and find exactly what you need. The airators come in both male and female thread and a variety of sizes so you really should bring it along to be sure. Also make sure you don't lose the rubber washer against the airator as you remove it or your faucet will leak when you replace the airator. You should probably buy an extra washer to use on your adapter if it doesn't come with one, so you are not haveing to swap it every time you make water.