Adapter converts the female threads of your faucet from 16.5mm to 55/64"-27 female threads of the diverter valve.
![](https://cdn.shopify.com/s/files/1/0112/7546/8859/products/16.5-Neoperl-Metal_480x480.jpg?v=1624898234)
NOTE - If your aerator does not have a blue o-ring, like the one shown on this adapter, don't order this adapter. Please contact me. Send me a photo of your aerator and I can tell you which adapter you need.