The Weider X-Factor Door Gym is a total-body training system that's engineered to attach to any standard door. The unique design and progressive resistance exceeding 210 pounds promote explosive movements to build strength and add muscle mass. Resistance is the key to any strength-training workout. With the X-Factor Home Gym's unique progressive bands, resistance increase as your body exerts more force. Each exercise promotes movements that strengthen your core and extremities via an intense, muscle-building, and fat-burning workout.