This instrument used in Holland can do calculations for currencies exchanges:

Guilders, Lira, Swedish Krona, French Francs, Swiss Francs, Belgian Francs, US Dollars, and Marks.

It consists of seven independent sliding rules.
Each sliding rule is assigned a currency.

On each sliding rule one can perform two types of conversion:

• Florin to the currency of the rule
• Currency of the rule to the US Dollars