The Box Four E-Bike Cassette offers high gears with more teeth to withstand the rigors of modern E-Bike riding. Adding an extra tooth to each of the three highest gears provides increased durability and decreased wear by distributing the load over a larger area!  Box Four adapts our Prime 9 philosophy of durability, simplicity, and reliability at a great price point. All cogs are stamped from steel, given our durable black coating and then the larger cogs are pinned to each other with spacers for easy installation.