Measure small items accurately with The Beadsmith's Economy Brass Gauge. Made of high-quality brass, the slide gauge is non-magnetic and durable, specifically designed for long lasting use. The caliper-like device can measure up to 3.14”/80mm, making it ideal for determining the size, thickness, or diameter of a bead, gem, diamond, coin, wire and much more. These instruments are conveniently marked with measurements in both inch and millimeter increments. To use, start with the gauge in a closed position, with the zero lines matching up. To measure an item, slide the gauge open and fit the item in securely. The measurements will be indicated on the right side of the item. This measuring caliper is small and lightweight, making it an excellent tool for daily carry and everyday use. These gauges are often used to display dimensional information in science & engineering but is convenient for creative use as well. Jewelry designers use them to determine the size of beads and gems, while seamstresses easily create patterns and buttonholes. It's also great for other DIY crafters and general home use too. Unlike digital or electric calipers, the brass gauge does not require batteries or die just when you need it. Handy and easy to use!