Green - Light - 1 ¾" wide
This band is also a good size for general use and for adding resistance to people from 140 to 200 pounds for body movements. Good choice for pull up training. Resistance is 50 - 120 pounds.

Blue - Medium - 2 ½" wide
For use getting started on training for bodyweight pull ups and adding resistance for elite athletes and people over 200 pounds. Also a good choice for adding increment weight to power lifts. Resistance 60 - 150 pounds.

Orange - Heavy - 3 ¼" wide 
Primarily used for adding weight to power lifts. Resistance is 70 to 175 pounds.