This handy frame is made of highly durable plastic with enough flex in it to be nearly unbreakable, yet rigid enough to always let you count your stitches and rows accurately. It can be a lifesaver whenever you knit a project where guage counts. Plus, addi has added a convenient needle gauge along the sides. Stitch/row gauge is 10cm x 10cm (the equivalent of 4 inches x 4 inches); needle gauge gives both metric and US sizes.