Spenco(R) Propel(TM) + Carbon Performance Insoles deliver explosiveness with each foot strike. Turn your everyday trainer into an elite race-ready shoe with the Spenco(R) Propel(TM) + Carbon insole. Designed by biomechanical experts, this insole features a carbon plate for explosiveness with each foot strike and INergy(TM) Foam for next-level energy efficiency. Fit & Design: Carbon Plate provides forward propulsion and explosiveness with each foot strike Responsive INergy(TM) Foam cushioning creates next-level energy efficiency Contoured and supportive heel cup Pack includes 1 pair of insoles