I had been the set of 4 with blue and red ribbon (plus one Thera-Band), the red ribbon had but now abandoned after a while, the blue was lost. In this set more than the yellow tape corresponds to the former red (light) band - even if any signs of fatigue in the older band into account. The difference in resistance between the red (supposedly middle) and the green belt is very low ... I had only now again here on the side look which should now be the stronger. They are to use both quite firm and for physiotherapy barely. Even with the yellow I have trouble with exercises that were carried out without any problems with the old red tape. Too Bad.