Go the mid-distance with the super light Brooks PR MD 54.26 track spike. The medial side has been improved with a built-in stretch material to secure the arch. Airy mesh upper keeps the weight down and increases breathability. Asymmetrical fit design, lightweight midfoot capture, stretch arch fit, super thin air mesh, and welded overlays. Pebax® Rnew six-spike plate,, EVA heel wedge, and ultra-thin sharkskin outsole. Includes 6mm spikes and wrench. Wt. 3.7 oz.