EVA foam provides support and comfort, while a Microtex cover with Cordura protection guarantees durability and abrasion resistance. K:IUM Rails K:IUM is a Fi'zi:k proprietary rail formulation. It's the combination of a particular metal alloy, a specific tubular design and a special finishing process which increases fatigue performance on the rail surface. Fact: 8% weight reduction compared to solid titanium. K:IUM features a high strength-to-weight ratio grade and high corrosion resistance. Wing Flex Technology Wing Flex shell has engineered flexibility along the edges where the inner thighs contact the saddle. By allowing this area to flex, the rider can achieve a full range of leg movement in a wide range of riding positions. Wing Flex allows the saddle to adapt to the rider rather than the rider having to get used to the saddle.