Made of a specially formulated co-polymer material. They feature performance characteristics that can not be achieved with natural rubber (latex) and other compounds. Made with an elastomeric compound, they are 100% latex free while retaining the dynamic stretch properties of latex preferred by most therapists and patients. Each band and tube has been clinically proven to provide consistent tension and evenly spaced resistance levels between each band level. Power and odor-free material is cleaner and safer to use. Non-slip surface for better grip. Buoyant and resistant to swimming pool chemicals. UV, sunlight and most infection control products resistant. Convenient dispenser system.