Slide rules

Alro unknown type B probably HaV

AL-RO was a company founded in the 1930 by Ir C.J. Dussel & A. Pasveer. Their uniqueness of the circular slide rules was the metal case, which not only protected the metal case, but also acted as a stand for desktop use. At the end of the 1950s the company stopped producing the circular slide rules.

The Oughtred  Society made a special article about these circular slide rules in 2006.

The diameter of this ALRO circular slide rule is 13cm. The metal is aluminium. Seems that is was made for commercial purposes as it mentions british standards.This is one of the older ones. 

This item  is in a good to very good .

If you want pictures in a better resolution, don't hesitate to email me.