1.Full-Body Muscle Engagement Technology: This professional-grade twister arm trainer activates 6and major muscle groups simultaneously through its U-shaped dynamic resistance system. Engineered for chest expansion, arm sculpting, back strengthening, and grip conditioning - ideal for compound functional training with 300 percent higher muscle activation than traditional spring bars 2.Spring System: Features triple-reinforced chromium steel springs with 50,000and cycle durability tested, delivering smooth 40-100lb progressive resistance. Anti-corrosion coating maintains consistent elasticity while noise-dampening tech ensures quiet home workouts 3.3D Ergonomic Safety Design: Patent-pending angled torsion bar with medical-grade silicone grips (9.8' circumference) prevents wrist strain. Memory foam palm cushions with sweat-wicking texture provide secure hold during high-intensity sessions 4.Smart Progressive Training System: Modular design allows instant resistance adjustment through detachable spring units - combine 2/4 springs for 3 difficulty modes (Beginner 40lb, Intermediate 70lb, Advanced 100lb). Includes digital workout guide with 25and professional routines for muscle growth/fat burning Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.