1. This rule is interesting for its "horseshoe" shaped cursor. The cursor has two hair lines for Ö(4/p) and (4/p) which can be used either with the central cursor or as a pair, depending of whether they are used with A/B scales or the C/D scales.
2. The well of the rule is entirely made of plastic. It is fitted into the stock in a groove in a way which one leaves a very thin layer of bamboo over the plastic. Small pins have been driven through the bamboo and plastic into the stock to reinforce the glue. On the back of the rule some of the pins seem to have been replaced by small screws (one of which is seen on the back detail).
3. The rule itself has no indication of model number - the only indication was on the box.