Flexible workout Resistance bands provides unlimited ways of working and are ideal for warming-up the lower and upper limbs and muscle-activation. They are an effective and versatile training tool that can be used to increase strength and stability in the upper and lower body. The resistance bands come in two pairs with different strengths (medium and heavy) with a smart bag to store them in. They are made in 100% natural latex, with certification of RoHS, free from phthalates. Always keep a pair of HERO resistance bands in your gym bag, wherever you are.