Mini Digital ProtractorLong press ""ON/OFF"" for 3 seconds to turn on the protractor. """"UNIT"""" key changes degrees or percentages. """" CAL """" toggles between absolute/relative mode, press ""CAL"" to enter relative mode, then press and hold ""CAL"" for 4 seconds to return to absolute mode. ""HOLD"" at the bottom saves the value so you never miss an important reading again. It's more useful and easier for your work. Strong Magnetic Base & LCD DisplayThe electronic level base has three magnets, which can be easily attached to any steel object. The level angle indicator has a large LCD display for quick level reading. When the product is reversed, the numbers are automatically reversed. Zinc Alloy CaseDifferent from other plastic cases, our digital protractor adopts zinc alloy case, which has good heat dissipation, waterproof, moisture-proof and beautiful appearance. Easy to carryThe magnetic protractor is a lightweight and portable measuring tool that can be carried anywhere. Especially useful for working on ladders, roofs or other unstable areas.