This is a replacement faucet adapter for a Panasonic water purifier, purchased about three years ago. I mistakenly bought the wrong model, so it didn't fit my faucet, and I'm selling it. It's a Panasonic water-related product fixture. Although it has not been used, it has been opened because I realized it didn't fit when I tried to install it. Product Name: Aerator faucet adapter (for internal thread) Part Numbers: PRV-D8623K PRV-D8623M PRV-D8623G