Sterling Currency Calculators
135 x 170 x 130 mm (5.3" x 6.7" x 5.1").
"Foreign Made", 1950s - 1960s.
Addition only by moving the wheels by finger.
Clear to zero by turning the crank.
A decimal version was also available.
These are fairly sturdily made calculators. There were also many cheaper all-plastic machines made.