Round 1-1/4" diameter steel plate, .023" to .025: gauge.
Galvalume Coated Steel.
Four key holes provide bonding of plaster and base coat to washer face.
Cavities allow exterior base coatings to bond to disk face.
Uses include securing lath and mesh to various substrates
Keyholes grab on to finish / plaster
Flattens on surface for minimal skim coat application