Two 3/4 in. ports on the front pressure relief valve and boiler drain valve. Designed to connect the water line from the pump to the pressure tank, this 13 in. long 1-1/4 in. Brass Tank Tee can be used with 1/4 in.
I formally fabricated this from many pieces of PVC. That took time and more space. The total cost was probably similar but the time saved and and fewer areas or possibilities of leaks makes it worth the investment.