AZ4X alloy construction provides increased strength and a higher response rate More responsive, optimized barrel design creates a sweet spot twice as large as the CAT6 2nd Generation AV2 Anti-Vibration knob features an upgraded, finely tuned harmonic dampening system for better feel and less negative vibrational feedback Ring-free barrel technology offers greater performance with no "dead spots" One-piece alloy construction provides a clean, consistent, traditional feel.