Wide Width: Fits Women's D to E and Men's EE to 4E

The 4 Step System comes with 4 interchangeable inserts that allow you to customize how Barefoot Science® works best for you – for reduced muscle fatigue

tactile sensory foundation and adds oscillating electromagnetic and tuneable harmonic resonance elements for the most advanced expression of the Biopods insole platform

Standard Width: Fit Women's A to AAA and Men's B to C

and relaxed movement

Narrow Classic Sneakers - Grey Biopods Bamboo Ankle Socks Wide Width: Fits Women's DEncourages healthy movement for daily life, sport, and recovery. Narrow Width: Fit Women's A to AAA and Men's B to C