Stretch Your Limits with the Acon Performance KitThe Air 13 HD Trampoline Package with Performance Kit is Acon elevation at its highest. With new Piano Wire Springs, the best bounce in the business gets extreme.Performance, All in One Package includes the signature Air 13 Sport HD trampoline, 2 sets of springs (Piano Wire and Air series), performance pole sleeves, gear bag and branded stickers.Acon Innovation Our safety skirt fits over the springs for greater safety and a quieter jumping experience. Only our 13 HD offers an adjustable two-way spring setup to switch the resistance between more controlled leaping or an additional boost.Our best bounce Meet new heights of performance with our farthest stretching springs for maximum energy in every leap. In a blind study with Gtrampers, groups rated the piano wire bounce of the Acon performance kit above both the leading competitive models.