The AirHeel™ Arch and Heel Support's clever design uses your natural gait to help treat plantar fasciitis, Achilles tendonitis and heel pain. The secret is two interconnected cells, which pass air back and forth as you shift your weight with each step. The cycling air creates pulsating compression to reduce swelling and discomfort, while promoting blood circulation. AirHeel's™ breathable fabric keeps your foot cool and comfortable all day, yet fits like a regular sock. Sizes: see chart. Imported.Lycra/Nylon. Tubing and Aircell are Polyurethane.