Design PhilosophyProtection – it’s in our DNA. An expanded line up of protectors ensures every type of mountain biker is catered for. We work with the best riders to develop our products including the first family of DH, the Athertons. The MT500 Hard Shell knee protectors provide the highest level of fully certified protection for peace of mind in the most extreme situations. D3O ProtectionD3O uses patented, patent-pending and proprietary technology to make rate-sensitive, soft, flexible materials with high shock absorbing properties. D3O\'s core technology applies non-Newtonian principles to materials which are engineered for shock absorption. Non-Newtonian materials stiffen on impact to dissipate impact energy and reduce transmitted force, before returning to their flexible state. 90 day satisfaction guaranteeSo confident are we in this product that, if you are not entirely satisfied with it then we offer a no-quibble refund or replacement policy within 90 days of purchase.