Early ZX Spectrums were manufactured with light-grey keyboards, later models with blue-grey keys. Other features of the case reveal more about this particular machine. The white sticker indicates a 48K model, 16K machines had a green sticker. Sinclair Research would regularly repair and upgrade machines. This example has been rewired and had a poorly fitting chip refixed.

Due to high failure rates, it is possible to find issue one boards with blue-grey keys, as Sinclair repaired and rehoused the boards before sending them back to the customer.