OATEY 72117 3" or 4" PVC General Purpose Drain w/ 6" SS Grate

Both. The Oatey 72117 is built to take either a 3 inch or a 4 inch PVC connection, so you can use it on either size DWV line without ordering a different body. It's a PVC drain, so it solvent welds to PVC pipe of the matching size.

No trap is part of it. The 72117 is the drain body and 6 inch stainless grate only, so you'll need to trap the line separately with a PVC P-trap sized to the 3 inch or 4 inch outlet you connect to, plus solvent cement and primer for the joints.

Stainless steel grate on a PVC body. For a utility room, laundry, or mechanical space where carts, mop buckets, or foot traffic cross the drain, the stainless top holds up better than a plastic strainer and resists corrosion from standing water and cleaning chemicals.

A general purpose drain handles incidental water, not a bathing fixture: laundry rooms, water heater pans areas, mechanical and janitor rooms, basements, garages. A shower drain is sized and clamped for a waterproof membrane or shower pan. The 72117 is a PVC body with a 6 inch stainless grate on a 3 or 4 inch outlet, intended for floor drainage duty rather than pan-tied shower work.

The 72117 is listed at 4 lbs with a volume of 0.147. Light enough to carry in on a service call, but the stainless grate accounts for most of that weight.