6mm Satin Stainless Steel Locking Elliptical Cuff with Updated Lock To Measure: Wrap a flexible tape measure around the thinnest part of your wrist or ankle (above the ankle bone). Start by adding 1/4" to 1/2". Flex your foot to make sure the cuff won't bind. Based on customer feedback, we suggest adding about 1/2" to your ankle measurement as this is proven to provide a comfortable fit.