Feet are like snowflakes: No two are the same, sometimes even those on the same body. So the Propulse 2 offers the option of customizing the lateral fit with a pair of Velcro straps, one over the midfoot and one around the heel. Think of these straps as seat belts that keep your foot from moving on side-to-side starts and stops. With a mostly mesh upper, the Propulse 2 delivers excellent ventilation when you’re heating it up from the baseline. Fans of the original Propulse will welcome this version’s roomier fit and, thanks to the use of softer materials, an overall more comfortable feel. The tiny grooves on the otherwise herringbone-style outsole mean the shoe works well on hard courts as well as on clay, letting you slide without digging up the dirt.