Vionic Spark Caroll - Women's Ballet Flat. The classic ballet flat gets an upgrade with Spark Caroll, featuring a soft elastic top line accented by delicate stitching and crossover detail above the toe cap, available in leather or printed leather. Contoured footbed for addictive support. Orthaheel technology helps promote alignment from the ground up. Deep heel cup provides essential stability. Stylish and comfortable footwear that incorporates a podiatrist designed biomechanical orthotic.