The Comptometer... It has no batteries... It's the first pocket calculator...
It was manufactured in the USA, by FELT & TARRANT MFG Co - Chicago, ILL
and distributed (sold) in Belgium by the Societe Belge Comptometer S.A.,
Avenue Louise No 32 - Bruxelles 5.
The museum is open from Monday thru Sunday from 00 AM until 11:59 PM - Entrance is free, so enjoy!
