Our Box Three tier delivers many of the same capabilities of its more famous siblings yet it's built upon a simpler platform. The cassette is E-bike Optimized at 12-50T. adding an extra tooth to each of the three highest gears. The derailleur exploits our Limited Slip clutch technology without the Tri-pack features. The action on the shifter is limited to one downshift per lever swing. although you'll forgo the hinged clamp and die-cast structure. And lastly. string it all together with a Prime 9 chain but without extravagant coatings. If you're looking to bring your 2/3 by bike into the 21st century. then level up with this group!