The Metzeler Six Days Extreme Hard 90/100-21 57M is a front enduro competition tire designed for hardpack, rocky trails, and abrasive terrain. Developed in the FIM Enduro World Championship, it features a hard-compound rubber that delivers maximum durability, resistance to chunking, and consistent performance on compact ground. The tall, reinforced tread blocks provide precise steering feedback, excellent braking stability, and reliable grip on hard surfaces. Its polyester carcass construction enhances impact absorption and handling while maintaining stability under aggressive riding conditions. With a 57M load/speed rating, this tire is competition-ready and trusted by professional enduro riders for challenging hard enduro events.