Unleash your speed during off-road adventures in the Altra Superior 4.5 trail running shoes! Every step on the Quantic(TM) midsole provides a lightweight ride, with an excellent response in a rapidly changing environment. Enjoy grippy traction on any terrain with the Maxtrac(TM) multi-directional outsole. When you feel like letting loose on the trail, let the Altra Superior 4.5 be your speedy guide. What's New? Updated upper offers better durability and protection for trail debris. Improved breathability and drainage for wet excursions and rainy runs. Who's it for? Adventurous trail runners seeking a fast and nimble shoe to blaze their own path. Shoe Technology Upper: Redesigned knit upper increases durability and breathability while providing a locked-in fit. Removable StoneGuard(TM) for lightweight rock protection. Midsole: Zero Drop(TM) platform encourages low impact landings and proper form. FootShape(TM) toe box lets the toes relax and spread out naturally, while the big toe remains straight for more stability and a powerful toe-off. Quantic(TM) midsole provides excellent responsiveness in a lightweight package. Outsole: MaxTrac(TM) rubber outsole provides sticky and sure-footed traction on any surface.