Drawing ruler with metal strips

Data:

• This is a black coloured timber drawing ruler with at each corner a metal strip, to prevent wear.
• It is made by Faber Castell and of high quality.
• At one corner the metal strip is slightly movable.

Questions:

1. Do you know other manufacturers of drawing rulers who have done similar?
2. The type of timber is not known. Do you have any idea? Boxwood? Mahogany?