The Danco Adapter is used to connect a female aerator to a female faucet. It has male threads on top and bottom. This adapter should be used with a device that has female threads 15/16.
From the Manufacturer
Danco is one of the largest plumbing repair, replacement and remodel suppliers in the home improvement industry. We are largely focused on empowering Do It Yourself consumers with affordable plumbing products and solutions which create new and refreshing décors for bathrooms and kitchens.