The Park Tool Derailleur Hanger Alignment Guide is an essential tool for any cyclist looking to maintain optimal shifting performance. Designed to measure and straighten misaligned derailleur hangers, this guide effectively resolves most shifting issues. Crafted from heavy gauge chrome-plated steel, it ensures durability and reliability. Compatible with a wide range of wheel sizes from 20 to 29 inches and all derailleur models, including Shimano Direct Mount, this 41cm tool is perfect for both professional mechanics and home bike enthusiasts.