The sock ruler is an innovative measuring tool for sock knitters that allows the sock to lie flat and ensure accurate measurements. No more messing around with tape measures. Whether you knit socks top down or toe up the Sock Ruler works for both. It will measure the length of the cuff, the distance from top of cuff to start of heel flap and the distance from finished heel to start of decrease for toe. This is the new must have tool for all sock knitters. Measurements are in inches