The Comandante coffee grinder is considered by many to be the ultimate manual coffee grinder. There's no question that Comandante pioneered the premium grinder space, and many still consider it the best example of the genre. What is particularly impressive about Comandante grinders is their ability to grind incredibly consistently at all ends of the spectrum, from Turkish to French press. So what could you possibly do to improve on that? The Red Clix competition axle changes one crucial thing about the Comandante, the only thing you could possibly want to improve: its precision. Specifically, the Red Clix gives the Comandante grinder twice as many steps, reducing the degree of change between 'clicks' from an already small 30 microns to a minuscule 15 microns. The Red Clix competition axle certainly isn't a necessity. You can get delicious brews without it, no question; however, in specific contexts where you want to fine-tune your extractions to the nth degree, this accessory can come in handy. We would say that this is particularly useful if you're using your Comandante grinder for espresso, where tiny grind setting changes can make a big difference, or, as the product name indicates, if you're participating in brewing competitions, where you are shooting for as close to perfect as possible (within 15 microns of perfect you could say). Comandante Red Clix RX35 Competition Axle features & specifications Upgrades the Comandante C40 coffee grinder to have double the amount of steps (works with all C40 models and the X25) Reduces step size from 30 microns to 15 microns Includes a new axle, new adjustment knob, two washers and a spring It gives you hand-grinding superpowers