EcoFLEX rubber is made of vulcanized natural rubber, with up to 30% recycled material made of scrap from medical industry manufacturing such as rubber gloves, or stoppers. Although it uses recycled material, it is extremely durable due to the strong and flexible nature of vulcanized natural rubber. It is also super grippy (think pink eraser or a new shoe sole). This run's flight numbers: 9 | 4 | 0 | 3.5 (Consistently overstable, but still workable) About this run: Super grippy, and our stiffest run yet for extra assurance on full power throws (but don't worry, it can still bend in half if you try). This run came out very flat topped and even puddle in some discs, giving this driver a super comfortable grip forehand, backhand, big hand, small hand. These characteristics + it's overstable flight make the ecoFLEX Gecko a dependable workhorse overstable driver.