We are hooking up the water supply to a single jacuzzi bath tub (No shower attached). We have learned that the 1/2 water supply going to the hot and cold will first need to encounter a shut off valve, then come out (continuing 1/2" through 'flexible' hoses provided with the trim to the hot and cold handles. We simple cannot find a shut off valve that is 1/2" to 1/2". All of it is 1/2" to 3/8" like for sinks. Where can I get this shut off valve and is it correct that bath tubs should be supply directly with 1/2" line? We've been using PEX if that helps.

If you want the valve inlet to be ½" female, the valve you need will have a 7/16" and ½" slip joint outlet, like a Brasscraft G23301X. ½" PEX has a smaller inside diameter than ½" copper, so depending on the flow rate of the tub valve, your tub might fill slowly with ½" PEX.

Steve don't you mean 5/8" x 1/2". If the inlet to the valve is IPS it will be 1/2" fips. It would be 5/8" if it is a ferrel for a 1/2" copper tube. Hope I made that clear. Take care

either use a pex ball valve an adapt from it to the faucet connector

or use a pex by 1/2 male valve (if that will work)

I was assuming ½" female pipe inlet.