Red (15-30 lbs): Suitable for preheating, stretching and mild strength training. Suitable for shoulder training and other high performance speed training.
Black (30-60 lbs): Mild to moderate resistance to movement and stretching.
Purple (60-100 lbs): Moderate to severe resistance to moderate fitness and strength training. Also suitable as a medium-sized support for pull-ups.
Green (70-120 lbs): Heavy resistance to heavy training, strong support in pull-ups. Suitable for speed and agility training such as push-ups, squats, bench presses and other exercises.
Blue (80-150 lbs):The most resistant one, perfect for people needing more help with their pull ups and bar muscle ups.