The lightest boot on the market! New for Spring Summer 2019 the Flexor Boot, features new & exclusive Recoil technology. Recoil: is a 3D print band positioned over the top of the foot. This acts in a similar way to the retinaculum that helps keep your tendons in place, preventing rolling of the foot. H10: barefoot feel rubber sole is ultra-sensitive soft and flexible, but still offers the same outstanding grip expected from a thicker sole.