Gold foil.
4cm wide - different lengths available.
All lengths come in a storage jar.
To use:
Gel polish - place foil on tacky layer of polish, just prior to top coat. This will ensure the foil sticks and is protected by the top coat.
Regular polish - place foil on polish that isn't quite dry, it should stick to the nail.
Use a top coat on top to protect the foil design.