Sinclair Instrument Wrist Calculator
The Sinclair Instrument Wrist Calculator was a simple 8-digit calculator, that was only sold as a mail-order kit. It was released in February 1977 by Sinclair Instrument, a company ran in parallel with Sinclair Radionics. It originally sold for £9.95 (plus VAT).
The wrist calculator ran on six mercury hearing-aid batteries, which only lasted about an hour and a half, and required the user to disassemble the unit to change them.
The calculator had a three-position button to access extra functions, such as memory and square root.
Sales were not great, only around 10,000 were reported sold. Reliability meant that a great many were returned to Sinclair, as was the case with the Sinclair digital watches.
Manufacturer: Sinclair Instrument
This exhibit has a reference ID of CH52845. Please quote this reference ID in any communication with the Centre for Computing History.