E*Thirteen Core E*Spec Chain Guide Lightweight, Durable Chain Retention The E*Thirteen Core e*spec Chain Guides offer a lightweight, durable chain retention solution for Bosch CX Gen4, Gen5, and Shimano EP8 motor systems, with 55mm chainlines. Core e*spec Guides are designed to provide the long-lasting performance of an alloy backplate guide, with a wider 55mm chainline for modern Boost and Super Boost e-bikes. They feature a wider offset to accommodate 2-piece chainrings, which often have clearance issues, and our latest e*spec upper sliders, which provide unprecedented retention while improving ease of setup and maintenance. Features Includes ISCG mounting hardware for 55mm chainlines Wider offset to accommodate 2-piece chainrings Adjustable upper slider and durable aluminum backplate | E. thirteen | Core E*spec Chain Guide 32-36T Gen 5