The 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. Surface: 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 percent 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 collar. Semi-curved training last provides full-length cushioning with shock absorption. Molded EVA midsole utilizes WaveSpring technology. Memory Foam insole is removable to accommodate orthotics. High-abrasion rubber outsole provides reliable traction. Imported. Measurements: Weight: 14 oz Product measurements were taken using size 9, width D - Medium. Please note that measurements may vary by size. Weight of footwear is based on a single item, not a pair.