The pearl izumi race rd model provides benchmark performance and fit in a light and affordable package with top of the line features like our 11 power plate with built in longitudinal arch support and the precision of the boa retention system select 11 power plate select grade nylon and composite fiber plate for lightweight stiffness and durability direct vent technology for cooling and drainage concave shaping for ultra low 70mm stack height enhanced plate stiffness and anatomic supp