Hi all. I am trying to replace my old kitchen sink faucet with a new one. It's a 4-hole sink. The current faucet is using three of the holes and there is something else occupying the 4th hole. This is my question: what exactly is this "something else" and is it really necessary? I'd like to use that 4th hole for a sprayer nozzle. The thing in the 4th hole now is connected by two tubes to the dishwasher and to the garbage disposal. If it is necessary to keep it there, I'd at least like to get a new one to match the new faucet because this "thing" looks like hell. Anybody know what this thing is called and if I really need it? It sort of looks like a small cylinder with a hole in the side. Maybe a vent of some sort? Overflow for dishwasher maybe? I will try to post a pic below. Thanks.