Black Watch (wristwatch)

The product was beset by technical problems, including short battery life, variable accuracy and a very sensitive integrated circuit which could be rendered useless by static shock.

In spite of this, Sinclair's advertising still claimed: The watch suffered from serious inherent design flaws.

[3] The quartz crystal was temperature-sensitive, causing the watch to run at different speeds according to the ambient temperature.

The LED display brightness was rather weak, making it difficult to read in well-lit environments.

This completely overwhelmed Sinclair's customer service department, which still had a backlog of watches awaiting repair two years later.