E*thirteens new direct mount e*spec chainrings use their new M3 narrow-wide tooth profile, which reduces weight without compromising the chain guide. By making their SL and UL chainrings lighter and nicer than their predecessors, they've adapted a similar design to work with Bosch, Brose and Shimano motor configurations. - Designed for e-bikes - Details: - Lightweight and durable construction, minimal aesthetics and updated M3 tooth profile - Range of use: City / trekking bike Rear derailleur - Gear ratios front: 1-speed - Gear ratios rear: 11-speed Material - Material: steel Chainrings - Mounting / number of holes: Bosch direct mount Main information - Compatibility: Bosch CX Gen4.