1977. The loss of the calculator market was due in part to technological development leading to smaller and cheaper components, which put heavy pressure on profit margins. An import levy of up to 17.5% was placed on components, but the duty for calculators imported from Japan or Hong Kong could be as little as 5%, making it unprofitable to produce calculators in the UK. Sinclair also had some problems with the reliability of earlier calculators that had adversely affected its reputation, but the Sovereign was sold with a "full and unconditional" five year guarantee. Design The Sovereign came in satin chrome and gold-plated models, with leather pouches and fitted wooden cases. It had an 8-digit seven-segment display that used red light-emitting diodes, with a decimal point to the right of each digit that could be illuminated as necessary. Power was provided by two 1.35 mercury button cells. The Sovereign measured , which made it small and sleek compared to other calculators of the time. The Sovereign was unusual because the casing was made from pressed steel, which gave it a much higher quality feel compared to injection moulded plastic. This allowed a variety of paint and plating options, including black painted, chrome-plated, silver-plated, and gold-plated, and a limited edition silver-plated version, inscribed to commemorate the Silver Jubilee of Queen Elizabeth II in 1977, were also produced. Asprey of London was rumoured to have produced two Sovereigns in solid gold, costing each. The design, by John Pemberton, won the Design Council Award in 1977, as the Executive had in 1973, and there are examples in the collection of the Museum of Modern Art in New York. Sovereigns are highly collectible, and used models command high prices. Functions As well as addition, subtraction, multiplication and division, it had reciprocal and square-root functions, and the ability to multiply by a fixed constant. With an eight-digit display, the calculator could display positive numbers between 0.0000001 and 99,999,999, and negative numbers between -0.000001 and -9,999,999. Calculators of the time tended to have displays of between 3 and 12 digits, as reducing the number of digits was an effective way of reducing the cost of the calculator. A number outside that range leads to an overflow, and the screen flashes and all keys except the clear key are rendered inoperable to inform the user of the error. An independent memory register could read information from the