4PCS Cache Aerator M21.5, Plug-In Faucet Aerator Faucet Restrictor Replacement Parts for Kitchen Cache Aerator Bathroom Sink Aerator with Key Removal Wrench Tool, 1.8GPM, 21.5mm/0.85inch

These worked great in my Delta faucet. I got 5 aerators plus the tool for less than $8.00. If I had ordered from Delta Faucets it would have been $22.40 for just one + shipping with no tool.

The part that goes up inside (see the white part in pic) is to big around.

For me, the threads on this were a bit too small and would not engage so it would just fall out. It is slightly smaller than 0.85" in diameter. I ordered 2 different generic brands, this being one of them, and they both had the same issue. Returned.

It worked really well as expected.The flow improved a lot

If you had an older delta kitchen faucet, look elsewhere. Purchased a bunch of these kits and even though it had the correct one (size wise) in the kit, it did NOT fit. Had to order the exact one, as I was getting ready to give up and buy a new faucet. After installing OEM part, I was back in business. I may use these on other faucets (if they fit lol)

These aerators fit and do aerate as needed. The key is included for easy installation. They appear to be a well-made as these parts typically and should function for a reasonable time. Overall, function as expected and I would buy them again.

I picked these up as replacements for two older aerators in my home. The style and measurements were exactly as described, and are working flawlessly. 5 stars!