- Skechers Kids' Nitro Sprint - Karvo Shoes Step up your pace in easy-wearing comfort with Skechers Nitro Sprint - Karvo. This lightweight slip-on sneaker features an athletic mesh and synthetic upper with a cushioned comfort insole. Product Features Athletic mesh and synthetic upper with stretch-laces Slip-on style with hook and loop closure Flexible traction outsole 1-inch heel Skechers® logo detail Cushioned comfort insole Shock-absorbing supportive midsole Item Number: 403753L.BKSL