Watts LF777SM1-20 3/4 3/4 In Lead Free Wye Pattern Strainer, Thread, 20 Mesh Screen, Tapped Retainer Cap

Both ends of the LF777SM1-20 3/4 are 3/4 inch female NPT threads, inlet and outlet. So it threads straight onto 3/4 inch threaded pipe or onto male adapters off copper or PEX. No unions or flanges are included, so if you want to pull the strainer without cutting pipe, add a pair of 3/4 inch male-thread unions.

Yes. The LF777S is a lead free strainer with a body and retainer cover of lead free cast copper silicon alloy, which is what makes it suitable for potable water service. Gaskets are EPDM and the screen is stainless steel.

Nothing is missing. This version ships as tapped without a closure plug, and the spec confirms no plug is supplied. The tap is a 1/2 inch female threaded blowdown outlet, so you finish it yourself: install a 1/2 inch NPT plug if you just want it closed off, or pipe a 1/2 inch ball valve into it for blowdown flushing without opening the cap. That valve or plug is a separate purchase.

Yes, within its rating. The LF777S is rated 400 PSI at 210 degrees F, with a minimum service temperature of 32 degrees F. That covers domestic hot water and typical low-temperature hydronic loops. Steam service is a different story, so check the actual operating temperature of the system before you install it.

20 mesh stainless steel is a general-purpose screen: it stops pipe scale, solder beads, weld slag, sand and thread chips ahead of pumps, meters, solenoid valves and backflow preventers. It is not a fine filter for silt or sediment polishing. If you are protecting something with tight clearances that calls for finer filtration, you want a finer mesh or a cartridge filter downstream instead.

The LF777S is listed as Buy American Act compliant, USA. That is the field a public-works or institutional spec normally asks for on a strainer line item.

A wye body hangs the screen pocket off at an angle to the run, so the pocket has to point down on horizontal pipe (or downstream on a vertical down-flow leg) for dirt to collect in it and drain out the blowdown. Install it with the cap accessible, since the 1/2 inch tapped blowdown on the retainer cover is how you flush it without breaking the line apart.

Same part. The 3/4 inch inlet is listed with a 20 MM metric equivalent size, which is just the nominal DN callout. The threads themselves are NPT, not metric, so do not try to mate it to BSP or metric-threaded pipe without an adapter.

No epoxy coating on this one, the coating type is listed as none. The bare lead free cast copper silicon alloy is the corrosion barrier, which is normal for a bronze-family potable water strainer. Epoxy lining is something you look for on iron bodies, not on this alloy.

Order it as Watts LF777SM1-20 3/4, series LF777S, Watts part number 124002. The "20" in the model is the 20 mesh screen and the M1 designates the tapped retainer cap.