A third longer screw goes into the wall. All three holes are 4.4mm dia and raised to take countersunk head screws. Plates are typically used in pairs, one either side.
LARGE Picture Hanging Brackets Brass Flat Wall Mirror Hanger Plate Fixing 38mm
16 Pcs Flush Mount Brackets, Interlocking Photo Frame Hooks, Heavy Duty Stainless Steel Picture Hanging Z Clip Brackets for Picture Display Art Gallery Wall Mount Frame, with 32 Screws
Flush Mount Brackets, Concealed Headboard Wall Fixings Brackets, Stainless Steel Heavy Duty Picture Hanging, Wall Mount Interlocking Z Clip Hook for Pictures, Mirrors Frames Hanging (Large-4 Pairs)
Picture Hanging Wire Kit 5 PCS 2m × Φ1.5 mm Stainless Steel with Wire Picture Hanging Hooks Wire Heavy Duty Adjustable Hook & Picture Rail Hangers Hold Up to 40 Kg for Picture Frame Photos and Mirror
1 Set Picture Hangers Set Picture Hanging Wire Picture Hanging Supplies Picture
