Green: 600 * 50 * 0.35 mm Pull value 5 ~ Weight 14 g
Blue: 600 * 50 * 0.5 mm pull value 10 ~ weight 16 g
Yellow: 600 * 50 * 0.7 mm pull value 15 ~ weight 18 g
Red: 600 * 50 * 0.9 mm pull value 20 ~ weight 29g

High-Quality Material: It is made of of high-quality TPE material, latex-free, skin-friendly，odorless, smooth surface, safe and durable, can maintain long-term elasticity, not easy to break.
Training And Rehabilitation: It is a high-quality elastic band product for resistance training and rehabilitation. It is ideal for resistance training, physical therapy and mobility training. Simple and effective resistance bands can stretch and tone muscle groups and improve your posture.
Suitable For People: Suitable for athletes, exercisers, the elderly, rehabilitation trainers, and the physical therapy bands can be used for physical therapy, rehabilitation, wrestling, bodybuilding, Pilates, yoga, etc. Simple but effective exercises will build strength and speed recovery.

These have different strength levels.