They are countersunk in the middle for a drywall screw and perforated to hold spackle to hide repairs.1" Zinc Plated Steel Ceiling Buttons 1000PK Plaster washers) are large diamater washers designed to hold up sagging plaster ceilings..
3/18"-16 x 1-3/4 in Phillips Flat Machine Screw, Zinc Plated Steel, 25 PK Commonly used with flat or lockwashers. Machine screws are used in fastening nearly all types of hard materials.
.3/18"-16 x 1-3/4 in Phillips Flat Machine Screw, Zinc Plated Steel, 25 PK Commonly used with flat or lockwashers. Machine screws are used in fastening nearly all types of hard materials.