The Zurn PN400-5B-GRID 5" Drain Cover is a component for commercial plumbing systems. It's designed to cover and protect the drain opening in floors or other surfaces. The 5" size indicates the diameter of the drain opening it covers. The GRID likely refers to the design of the cover, possibly featuring a grid pattern for enhanced drainage or aesthetics. https://partsfe.com/pn400-5b-grid-zurn-drain-cover-5