The Extreme model, for Strong Athletes and/or heavy people. KJ Pro7, with the new support plate, can return up to double the energy compared to the standard XR series models for the general public. It includes the versatile T-Springs TS-Pro6 plus 2 steel coil springs, which can optionally be added on the T-Spring, to make the spring system even harder to compress. The KJ Pro7 incorporates all the latest patented technology and is the most effective, efficient and versatile product available in its category. KJ Pro7 IPS (spring system) is harder to compress. It can return up to 100% more energy than the XR series models. The shells are wider and longer. Their new, patented T-Spring design is the most versatile developed to date: you can add a strong steal spring in-between the 2 bands, to adapt the compression to your workout. For instance, plyometric exercises (explosive strength training) require a maximum compression resistance. Jogging a milder one.

Versatile high-density rubber platforms work to stretch and strengthen the Achilles tendon and calf muscles. Developing muscle resiliency in the area is vital to explosive leg power. Jump Soles will blast your lower legs like nothing else you've ever tried. After training with Jump Soles , you'll run faster, jump higher and change direction quicker. Also includes detailed training manual and video.