Crude steel.

This magnetic sheet is made from an optically elegant yet non-magnetic material which is subsequently magnetised. Crude steel directly from the rolling mill and 2 mm thick.
It is a pleasure to appreciate the charm of the material - at first sight it is impressive, but always worth a second look as the surface reacts to changes in humidity, temperature and light, shimmering from grey and green to blue - and can be brightened up with a little polish. Rust is not a problem except in humid environments.
Board and trim are fixed to the wall by means of adjustable screws and hexagonal nuts (see photo). Both steel and brass cap nuts are provided.