Versus X models are for riders who want a Fi'zi:k saddle with a relief zone. This is a solid-base saddle with a 20mm-deep ergonomic channel spanning its entire length, set between two specifically-formulated double injections of foam. The Fi'zi:k Aliante Versus X Braided Saddle carbon braided rail reduces weight and increases saddle stiffness. If you have a relatively low degree of spinal flexibility (more than 90 degrees between your straight legs and back when bending over as far as you can, keeping your legs straight a shoulders' width apart), you are a Bull. Your degree of Spinal flexibility will top out quite quickly when attempting to adopt the performance position. For this reason you will rotate you pelvis fully. You will benefit from the increased curvature (support) of the Aliante shape.