Review on Plumb Shop SF0080 Flexible Faucet Spray Aerator and Sprayer | Fits Most Threaded or Non-Threaded Spouts | Slips Over Spout End by Noel Schmits

I use such adapters for faucets instead of small ones that screw on. I've found that almost all spin-on models are set to spray and return to full flow settings when you turn off the water. This is because the water pressure is strong enough to hold the spray setting. This is normal if you normally use the full flow setting and use the spray setting from time to time. If, like me, you keep the spray mode on all the time, you'll find that whenever you turn on the water, you turn it on. Another thing is if like me you reduce the flow a bit you will find on most of these types that the water flow will drop to full flow and not stay in the spray. This type is a bit easier for me to use. The main disadvantage of this type is the way they walk. It can be very difficult to stretch the rubber enough to fit over the faucet head. (I find a little petroleum jelly or something around the rim makes it easier to tighten, but don't use too much as it can result in it not holding the faucet head tight enough and coming off too easily.) One more thing. When the rubber wears out and begins to crack, it must be replaced, otherwise the crack will sooner or later begin to flow. I've tried different types of screw caps, both plastic and metal, but I've found these work the best for me.