1/2″ Solder × 3/8″ Straight Stop Valve — Quarter-Turn Chrome Shut-Off

When the supply stub coming out of the floor is copper, not PEX, this is the stop that belongs on the end of it. The inlet is a 1/2″ female sweat socket — slip it over a copper stub, sweat the joint once, and it's a permanent, leak-proof connection with no ring or ferrule on that side. The 3/8″ compression outlet then takes a standard flexible riser up to a faucet, toilet, or dishwasher with just a nut and ferrule. Inside is a quarter-turn ball rather than an old multi-turn washer stem, so it seats positively and won't seize half-open after years untouched under a vanity. The body is lead-free brass under polished chrome, clean enough to leave exposed beneath a pedestal sink or open console. One solder joint, one compression nut, and the fixture has its own shut-off.