Our new 17.5mm Ultimate genuine latex rubber is formed using the mandrel dipped layer process where the inner layers remain natural and the outer layers are carbon impregnated. This high-tech process is designed to extend the life of the natural latex enhancing the physical properties of the rubber and offering up to 1000% elasticity. If you have been using 20mm rubber in the past this is what you can now use.Imported from the USASold by the meter.Recommended rubber length, adjust accordingly if the bands are too hard or too soft for you: