If you're a tennis player who breaks strings often

30 strings are an excellent option

Patellofemoral Syndrome

no batteries needed

Outsole: DuraTread™ outsole excels on dry dirt and rocky terrain

OOFOS OOahh Women's Nomad Size:9 If you're a tennis playerTreat your hard working feet to sweet relief in OOFOS Ooahh sandals. Featuring OOfoam technology, these slide on sandals absorb 37% more impact than your regular footwear. This special technology reduces stress on your feet and facilitates recovery after physical activities. Reduces stress on feet, knees, and back. Promotes a more natural foot motion. Features a minimalist, lightweight construction and an agile OOfoam strap for additional support.