Direct power transfer. 104 BCD flexibility. Upgrade your e-bike with e*thirteen's 104 BCD Spider, designed for seamless compatibility and efficiency. This spider enables the use of any 4-bolt standard chainring, offering a practical solution for cost-effective and eco-friendly chainring replacements. Made from durable 6-series alloy, it balances lightweight strength with the flexibility to pair with both long-lasting steel and lightweight alloy chainrings. PRODUCT SPEC Chainline 55mm Color Black Compatibility Compatible with all 104 BCD chain rings for Bosch Gen 4 Material Forged and CNC optimized alloy for stiffness and lightweight Weight 92g