These gauges are perfect for sizing unmarked needles and measuring swatches, and are sized to fit conveniently in knitting bags and notion pouches.  The large size is 8"/20cm long, and measures needles with diameters from 1.5mm/US000 to 19mm/US35.  The smaller ruler measures up to 5" / 12cm, and will size needles from 1.5mm/US000 to 10mm / US 15.