Lifeline Pull Up Revolution Assistance System to Improve Arm, Shoulders and Chest Strength with Assisted Pull Ups and Chin Ups Unique design allows pull up assistance throughout entire motion to progressively get stronger-decrease assistance over time Perform more, higher quality reps with proper form past muscle exhaustion Improve arm, shoulders, and chest strength with assisted pull ups and chin ups Easily add or subtract secure cables from 1 to 3 cables to vary assistance Heavy Duty Bar Hook attaches easily to pull up bar, integrated strap lock allows fast strap height adjustment