We love our leather wrist rulers at the shop — we are always whipping them on and off to measure gauge swatches in knitting and seam allowances in sewing! The newest version is a cool thin band with 1/4 " markings and a magnetic closure.
Sizes are based on wrapping around your wrist twice. Give it extra length depending on how loosely you want to wear it. The thin ruler fits more loosely than the traditional leather wrist ruler, more akin to wearing bangles.
Wrist Ruler is made in the US.