This is the hex nut that you will need to connect your tail piece barb to any faucet shank.
Please note: The shop will be closed on Saturday the 18-Oct-25. I will be open the evenings of the 15th, 16th, and 17th from 6-9 for anyone wanting to pickup an order before the weekend, just place your order as normal and email me to let me know when you'd like to stop by.