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Plus Adder

PLUS 506/D/815.357

PLUS Model 506/D/815.357.

Made in England by Bell Punch Co. Ltd. and distributed by Sumlock Compometer Ltd.

Key-driven ("Comptometer") type.

310 mm wide, 375 mm deep, 150 mm high (12.5" x 15" x 6"), 11.5 Kg (25.5 lbs).

185 mm x 180 mm x 127 mm. (7.25" x  7" x 5").


One of the more minimalist calculators made. Has 6 decades of keys, with only 1 to 5. To enter a number between 6 and 9 two keys have to be pressed in that column.

The knob on the right is for clearing the total.


Capable really only of adding lists of numbers to 9,999,999, but capable of doing this quickly and accurately (and cheaply !).

Click here to go to Sterling currency "Comptometers".

Vintage Calculators

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