"Breathing Sole"! IFME's indoor shoes with special processing to eliminate foot stuffiness (Patent No.: 5468059). Ventilation holes are placed on both the outsole and insole. They circulate air, releasing heat and moisture to prevent foot stuffiness. The outsole is designed to bend both vertically and horizontally to fit the foot, flexibly accommodating movement in all directions and not hindering the foot's natural movement. I bought different indoor shoes than usual, but my son didn't like them. They've only been tried on. Includes an insole for adjustment.