1. This rule was made in the former East Germany.
2. The slide is the same colour all through, this is not unique but it is rare. Most rules with colour have the colour applied on to white plastic. Personally I find the colour, a sickly peppermint green, to be a bit yucky.
3. Although this has a sub-set of the scales of the Darmstadt rule from the same maker the scale arrangement is different.