Quantum is an evolution of wireless gear shifting. You are no longer trapped in the expensive ecosystems of existing systems. Now you have the freedom to apply wireless shifting to any rear derailleur in just a few minutes, and at a very economical cost. Quantum is fully programmable for any number of speeds. Weighing about 50 grams, it is the lightest shifting system available. We have a wide range of adapters that will allow you to mount Quantum directly to a rear derailleur, or frame mount.