Cable may be 12mm over the plastic, but the wire is much thinner
I had a problem with my favorite bike locck - now fixed - and decided I should find a replacement. The 1m length is perfect for two turns fitting over the handlebars, andd long enough for a lamp-post or bike rack. But my old one had about 12mm steel, with a thin plastic covering, not only much stronger but harder to fit into bolt-cutters. This one can serve as an emergency lock, but I would not like to rely on it.
Probably a really good lock for a child's bike.