Engineered to perform. Featuring a new Adjustable Slit Upper that wraps and supports the foot plus an updated DuoSole® outsole for enhanced traction and flexibility, the GEL-DS Trainer® 23 builds on its predecessor’s powerful reputation to deliver a lightweight, speed-focused run each and every time. The FlyteFoam® midsole stimulates bounceback while the Propulsion Trusstic® Technology works with your natural anatomy to propel you forward as you move through your gait cycle. Weight: 8.4. Heel Height: 20mm. Forefoot Height: 10mm.