The Shimano Deore CS-M6200 is a 12-speed MTB cassette built entirely from steel cogs for maximum durability and consistent shifting performance across the full 10-51T range. HYPERGLIDE optimized tooth profiles keep shifts fast and smooth even under load. What Our Gearhead(R) Experts Are Saying: "All-steel cogs hold up to hard use without the shifting feel degrading over time, even after Shimano reduced material for a lower overall weight. The 10-51T range handles everything the trail throws at it without running out of gear on the steep stuff."