Speed Force II is our lightest performance shoe, weighing in at 6.5 oz. per shoe (M9). If you take out the removable insole for an even more barefoot feel, the shoe weighs even less! The biggest change: a new, elegant, super-breathable upper with welded components for extra durability. The iconic, adjustable instep and midfoot straps are not only eye-catching, but functional, giving you a confident, secure feeling for whatever you do in the Speed Force II. With a flexible 4.5 mm thick FeelTrue™ rubber sole, your brain gets the feedback it needs to help you move effectively, efficiently, and enjoyably.