The Rivera 2 features:

• Footshape™ comfort gives your feet more space to sit naturally and is designed to address biological differences in men's and women's feet.
• Balanced Cushioning™ platform positions your heel and forefoot at an equal distance from the ground, encourage better alignment, better form and a low-impact landing.
• Altra EGO™ foam is designed to provide added energy return and a responsive, yet soft, comfortable feel.
• Innerflex™ grid-like grooves in the middle are designed to provide flexibility and movement.
• Footpod™ Technology actually maps the bones and tendons of your foot to encourage natural movement underfoot.
• Engineered mesh upper.