The problem with current cord manufacturing is the rubber suppliers refuse to provide the date the rubber batch is manufactured. This causes issues as rubber looses tensile strength over time. The other issue with bungy rubber is that air shipping is also the only safe method of procurement. Ocean shipping logistic companies routinely leave the product warehouses or yarded in the tropical countries of origin for upto a month. These warehouses and yards and the boats the product is shipped on sustain temperatures of 28 to a peak of 40° Celsius (104° Fahrenheit) for extended periods which massively degrade the longevity and tensile strength of the rubber. This data has been tested using environmental tracking devices designed for quality control of shipping products. Many bungy companies struggle to maintain consistency of their cords because of this issue combined with the expense of air shipping. Rubber manufacturers take no responsibility for the off label use of their rubber and refuse to release engineering certificates or turgidity or elastomer certificates. Go Bungy International is the only company globally to manufacture rubber for the specific purpose of bungy. GBI rubber is manufactured and stored at the correct temperature and is tested for it’s consitency and elastic properties. We can issue certificates of authenticity.