Mavic ksyrium ultimate ii road shoeswith technologies such as the energy carbon outsole ergo dial retention system and endofit tongue the ksyrium ultimate ii displays many of mavics high end features designed to make long rides more comfortable this shoe also delivers when it comes to performance the energy carbon outsole is constructed of light stiff and thin carbon the low stack height of 7mm means that your foot will be closer to the pedal for improved power transfer with 5mm frontre