This is a VESA mounting plate for the HP Engage 16t touch monitor, a metal bracket that bolts to the back of the display and exposes a standard VESA hole pattern so the 16t can be fixed to a wall arm, pole stand, or POS terminal mounting bracket instead of using HP's own tilt stand. The Engage 16t is a 15.6" Full HD touch monitor built for POS use, and a separate VESA plate like this is how it's fitted to a countertop pole or wall mount in installations where HP's stand-mounted configuration isn't the right fit for the counter layout.