The RaceFace Bosch Gen 4/5 spider allows the use of 104 BCD rings on ebike cranksets (52mm chainline). This spider is only compatible with Bosch Gen 4/5 motors Any RaceFace 104 BCD chainring will mount securely with the included hardware including the RaceFace SHI-12 speed rings Aluminum Color Black Chainring BCD 104 Designed for ebike Yes Defined Color Black Direct Mount Type Direct Mount Bosch Gen 4