These bands provide progressive resistance exercise for all of your rehabilitative and fitness needs. 99.998% FREE of soluble proteins (Latex Allergens) . No messy powder. Easy to remember ROY G. BIV Progressive Resistance System. Available in prepackaged 4 foot pieces. The BodyTrends Fitness Bands come in two prepackaged sets: one for lighter resistance exercises and the other for a workout using heavier resistance. The Light pack contains: Three 4-foot pieces of Yellow, Orange and Red (thin medium and heavy resistance) . The Heavy pack contains: Three 4-foot pieces of Green, Light Blue and Navy Blue (extra heavy special heavy and super heavy resistance) .