104BCD 42T Bike Chainring Chain Wheel Gear Adapter for Mid Drive Motor M400 M300 M200 M215 M410 M315 M420 Features: 42T mid-motor chainring with protective disc to ensure stable and smooth chain , prevents the chain from scratching the bike frame. Chrome vanadium steel chainring and aluminum alloy protective disc, strong and with nice durability, wear-resistant, not easy to rust. Positive and negative tooth design, effectively prevents the chain from falling off. Compact and lightweight, will not bring burden to riding. Easy to install and use, suitable for M400 M300 M200 M215 M410 M315 M420 mid drive motors. Specifications: Model: Chainring Kit/ Chainring Base(optional) Color: Black Material: Aluminum Alloy(Protective Disc+Base) + Chromium-Molybdenum Steel(Chainring) Applicability: M400 M300 M200 M215 M410 M315 M420 Mid Drive Motor BCD: 104BCD Protective Disc Diameter: 185mm/ 7.3in Chainring Diameter: 175mm/ 6.9in Item Weight: Chainring Kit: 285g/ 10.1oz                      Chainring Base: 75g/ 2.6oz Packing List: 1 * Chainring Kit