The Hareline Bead Sizer and Measuring Ruler is a handy item to have on the tying bench for any fly tyer. The Bead Sizer and Measuring Ruler is 6 3/4 inches in total length. One side is a metric ruler and marks down to 0.5mm. The other side is a standard ruler down to 1/16 of an inch. Holes in the ruler allow for the quick measuring of beads from 1/16 to 1/4 inches in diameter. Determining bead sizes was never easier. Constructed of stainless steel.