"What Our Gearhead® Experts Are Saying: ""I’ve used the M21 on a couple of older mountain and hybrid builds, and it always surprises me. The shifting feels responsive, and setup is straightforward. It’s a budget-friendly derailleur that still handles tough rides without skipping a beat, making it a solid choice for keeping older drivetrains running smooth.""We love when affordable components perform beyond expectations, and the M21 Rear Derailleur 6/7 Speed delivers just that. Designed by microSHIFT with the same kinematics as their higher-end models, this derailleur brings crisp, reliable shifting to 6- and 7-speed drivetrains at an accessible price. Built with a durable steel cage and composite outer link, the M21 holds up well to everyday use, whether we’re climbing rolling trails or commuting in all conditions. It’s a dependable way to keep our bikes rolling with confidence, even when miles start to add up."