Powercore Tone Loop SetThe Tone Loop bands, being inexpensive, will add resistance to your workout, anytime and anywhere you are. You can benefit by using Loop bands in a variety of exercises, which can improve your training. They come in different strengths, Yellow ? extra light, Green ? light Red ? Medium Blue ? Medium Heavy. If you are unsure of how to use the bands, please feel free to visit us in store or ask one of our salesman to explain over a phone call or email.