Imperial RG0019 Return Air Grille, For 12 x 6 Opening, Steel, White

I thought I was gettin a wall grate but it turns out it was a baseboard grate. So I couldn’t use them because they would have stuck out too far. The width and height dimensions were listed when I bought but not the depth. Had I been experienced I would have known I was ordering the wrong part but I am not. A $25 lesson in how to purchase duct grates.