These flowers are slightly domed (not flat).

24 gauge sheet metal
These brass blanks are stiff and quite sturdy (not thin or flimsy)

Size: 20mm x19mm ( 3/4" x 3/4")
Hole size: 1mm
Thickness: 0.5mm

Quantity: 10 charms

Flat blanks. They can be hammered flat, textured, inked, stamped, pierced ~ so many options!