This new micro hole ultimate super strength genuine USA latex in 15.5mm packs more punch than the older standard 16mm rubber of the past. This rubber has a smaller internal hole which allows for more latex layers. USA latex rubber is formed using the 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.This rubber really has some power.Size: Available by the meterRecommended rubber length, adjust accordingly if the bands are too hard or too soft for you: