Product safety is a primary issue concem when designing, testing or, indeed, purchasing a product. A product may be unsafe due to a fault in either the manufacturing process or the design process. A fault in the manufacturing process will lead to a product not functioning as it was designed to. For example, the locks on a folding baby buggy may fail to engage properly when the buggy is unfolded, causing it to collapse. Such safety faults can be identified through extensive testing, and problems with the production quality, strength or tolerance of components can then be resolved through production design changes.