| CPC A42B 3/064 (2013.01) [A42B 3/06 (2013.01); C08L 73/00 (2013.01)] | 15 Claims |

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1. A helmet, comprising first and second components having a sliding interface between them, wherein the sliding interface is provided between respective sliding surfaces of the first and second components, and the first component comprises a polyketone, wherein the polyketone has a density of 1.10 g/cm3 to 1.27 g/cm3.
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