Slide rules
Alro Muiderkring
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 Alro Muiderkring was made around 1963 and has electronic scales, mostly for radio frequency purposes. The diameter is 13cm. The metal is aluminium.
This item is in a very good, like new .
If you want pictures in a better resolution, don't hesitate to email me.