Watts 6550047 3/8 IN Lead Free HydroGuard Under the Counter Lavatory Combination Mixing Valve, Rough Bronze Finish

All three ports on the Watts 6550047 are 3/8 inch compression joint: hot inlet, cold inlet, and the tempered outlet (3/8 inch, 10 mm). That means it drops into a typical lavatory rough-in on 3/8 inch supply tube without adapters or soldering, which is why it works under the counter on a finished job.

It leaves the factory set at 105 degrees F and is field adjustable from 80 to 120 degrees F. For a public hand-washing lavatory most facilities dial it in near the factory setting, so many installs need no adjustment at all.

Rated flow is 0.5 to 4 GPM, with 4 GPM capacity. A single modern 0.5 GPM metering or sensor faucet uses a fraction of that, so one valve can feed a small bank of lavatories as long as the total simultaneous demand stays inside 4 GPM and never drops under 0.5 GPM. Below 0.5 GPM the valve is outside its control range, which is the usual reason a single-lavatory install misbehaves.

Yes. The body is a lead free copper silicon alloy, which is what makes it acceptable for potable hand-washing service in healthcare, school, and hospitality lavatories where older brass bodies are no longer allowed.

Minimum static pressure is 5 PSI and maximum working pressure is 125 PSI. That low 5 PSI floor means it will still function on gravity-fed or low-pressure systems, and the 125 PSI ceiling covers normal municipal supply. On a service over 125 PSI you need a pressure reducing valve upstream.

No cold water bypass on this one. Everything leaving the outlet is mixed water, so you cannot use it to feed a fixture that needs separate full-cold service. If a project spec calls for a bypass, specify a different HydroGuard configuration.

Practically, no. The 6550047 is a rough bronze body meant to live in the cabinet or chase below the lavatory, not to be seen. If you need a polished or plated trim appearance at an exposed location, this is the wrong part to specify.