Therafirm mild support 15-20 mmhg knee-high stockings are designed to improve circulation relieve tired heavy aching legs and prevent mild swelling. true gradient compression delivers a controlled amount of pressure greatest at the ankle and gradually decreases towards the top of the compression stocking to promote better blood flow.  the compression stocking has a soft comfort band which is non-restrictive while staying in place all day.   be sure to use the size chart and measuring instructions to determine best size and fit.   size ankle calf length small 15.9cm - 18.4cm 26.7cm - 33cm 27.9cm - 38.1cm medium 19.1cm - 22.9cm 29.2cm - 35.6cm 30.5cm - 43.2cm large 22.9cm - 25.4cm 31.8cm - 38.1cm 33cm - 45.7cm x-large 25.4cm - 28.57cm 34.3cm - 40.6cm 35.6cm - 48.3cm xx-large 28.57cm - 31.8cm 36.8cm - 43.2cm 40.6cm - 53.3cm xxx-large 31.8cm - 34.92cm 41.9cm - 52.1cm 40.6cm - 53.3cm xxxx-large 34.92cm - 38.1cm 50.8cm - 61cm 40.6cm - 53.3cm "