The men's KARHU Fusion 4.0 is sure to elevate your run and propel you forward. The Fusion 4.0 provides a plush and propulsive ride ideal for the neutral runner. New additions and adjustments to the Fusion 4.0 make this shoe exceptional at seamlessly accelerating the transition from heel to toe-off, ensuring a responsive underfoot experience regardless of pace. This update utilizes soft IdealKnit mesh for improved breathability and comfort. Most notable is the incorporation of new nitrogen-injected AeroFoam in the midsole. This upgraded foam provides increased rebound, while the addition of a deflection channel at the bottom of the midsole helps absorb impact and provides a more cushioned experience. The KARHU Fusion 4.0 is the ultimate all-in-one shoe for runners seeking a unique blend of comfort, responsiveness, and performance. At KARHU, we know every runner has unique feet, and it's this as our starting point that has resulted in the newly updated Fusion 4.0. The Fusion 4.0 is also available in a wide fit, KARHU calls this High Volume (HiVo).