The features of appearance that result solely from the technical function of a product cannot be protected as a design. The components of a complex product are protected only if they are visible during the normal use of a product and if they are new and have individual character. Design features enabling one product to be functionally fitted or aesthetically matched to another are excluded from protection. These so-called 'must-fit' and 'must-match' exceptions are influenced by the need to ensure that third party providers of spare parts should not be unfairly prevented from competing within the spare parts market.