Wolf Tooth's CAMO stands for Chainline and Material Optimization. Available in various chainlines and spider configurations, CAMO spiders allow the use of previously unavailable chainring styles, materials, and chainlines in a lightweight, modular, and customizable package. These spiders are for use with e*thirteen cranksets that have removable spiders/chainrings and are only compatible with CAMO rings and bolts. One chainline option is available for e*thirteen cranks. The number and letter refer to the mm offset and direction from the mounting face to the centerline of the teeth: - M8 (minus 8mm - dished toward the frame): For 49mm chainline, designed for bikes with 135mm QR, 142mm thru axle, and some 148mm bikes.