SIZE CHART: S: length 8cm, width 4.5cm, heel thickness 1cm, front thickness 0.2cm M: length 9cm, width 4.8cm, heel thickness 1cm, front thickness 0.2cm L: length 11cm, width 6cm, heel thickness 1cm, front thickness 0.2cm MATERIAL: GEL, magnet Suitable for X/O legs, X/O feet, foot valgus, etc., improve heel inside and outside grinding shoes. Help stop back, ankle, knee and hip pain caused by wrong walking Soft heel cups have a sculpted, curved base to keep the heel in alignment as you walk The shoe inserts allow to balance the strength of the feet. This prevents inward or outward rolling, relieves pressure from the back, ankles, knees and hips, and changes O/X leg posture. Simply place the Correction Gel Heel Pads in your shoes to correct inward or outward roll and ensure proper alignment.