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! INCLUDES Box Three Prime 9 Single Shift Shifter Box Three Prime 9 X-Wide Rear Derailleur Box Three Prime 9 12-50T E-Bike Cassette Box Three Prime 9 126 Link Chain Polished SUPPORT MATERIAL View Prime 9 Drivetrain Compatibility Manual View Prime 9 E-Bike Comparison Chart How is the Ebike variant different? Why Prime 9?