The thickness is 1,1mm.
Plates are mirror-like polished and protected by a plastic film.
Several sizes are available:
9x12cm / 10x15cm / 15x20cm / 18x24cm / 24x30cm / 30x40cm / 40x50cm
Zinc is commonly used for etching and aquatint. Users prefer copper, more flexible, for dry techniques.
The mirror-like finish does not retain much ink and gives a white background to the prints.