Uniqueness Reduce Lower Back Strain 1  Decreases lower back muscles activities by 60%; 2  Increase productivity by 50%.   Passive with No Power 1  No batteries, no acutators, no computers; 2  Waterproof, dust-proof and easy to maintain.   Optimized Support 1  Minimal inhibition of arm, leg, and torso motions; 2  Support force optimized based on bending angle.   One-size-fits-all 1  For a wide range of height and waist sizes; 2  Instant change of support force for different tasks, and fatigue level.   Two Models 1  Model S: slightly lighter; 2  Model AC: compatible with LegX and ShoulderX.