Fizik antares vs kium saddlevs models are for riders who want a fizik saddle with a relief zone this is a solid base saddle with an ergonomic channel spanning the length of the saddle the saddle features a 5mm deep central relief channel kium is a fizik proprietary rail formulation its the combination of a particular metal alloy a specific tubular design and a special finishing process which increases fatigue performance on the rail surface fizik spine concept antares vs is for the