Foot Belt Technology: This feature includes two independently adjustable straps that allow for precision adjustment. The strap behind the foot tightens the heel area and reinforces the ankle support. The strap over the instep provides more support and fit adjustment. The ergonomic TPU counters at the heel provide for for strong heel support Exact Pro: This feature is located under the forefoot and was designed exclusively for tennis. It provides increased reactivity with every step. Vibrakill: This is a high performance shock absorbing material located under the heel. Michelin High Tech Sole: This material was designed exclusively for the Propulse shoe to provide more wear and tear than other shoes. Its seamless circular micro-cells (OCS) provide optimized traction and energy transfer.