This is a Half Inch Male to 1/2 inch Female Adapter John Guest PI011604S
It connects 1/2 Inch Male Tube to 1/2 inch BSP Female Thread
We use this to help people change from filters like Brita or Hot tap / Boiling water filter systems to our more economical water filter alternative that will save a lot of money in the long run.
We combine this part with other parts to reduce it down to the classic 1/4 inch OD tubing – standard in water filters. You can buy them together here
To see how to convert your tubing to another size checkout this chart of common conversion sizes
Product Code: PI011604S