ImportedSurface: Road. Differential: N/A. WaveSpring? Technology? Unique design integrates lightweight, stainless steel springs, one in the heel and two in the forefoot.? Springs provide both shock-absorbing cushioning and return of up to 96% of energy? Mechanical cushioning is designed to reduce stress on joints.? Designed to last for the lifetime of the shoes. Breathable mesh upper with no-stitch synthetic overlays. Traditional lace-up closure. Cushioned tongue and coThe long-awaited Spira? Aquarius utilized WaveSpring? technology with lightweight construction to offer an exceptionally comfortable, high-cushioning option for your workouts.Predecessor: Odyssey.Support Type: Neutral.Cushioning: High energizing cushioning.