They're extremely flexible to allow your feet to still be feet (your feet have 33 joints so yes they're made to flex, articulate and rotate!).
They're flat, unlike most insoles which are higher at heel, making your body have to constantly compensate for this leaning forward position. The body is best aligned when feet are flat on the ground (hopefully you're wearing barefoot or minimal footwear with no heel to toe drop!)
They're ridiculously comfortable – instantly turn your most uncomfortable shoes into your most comfortable.
The Legacy and LegacyThree insoles are designed to contour the foot and absorb energy: With our ability to contour the foot we distribute weight over a greater area, reducing pressure. And when we absorb energy the same thing happens – we reduce pressure! When pressure is reduced comfort goes UP!