There are powerful built-in magnets on the base which secures the attachment to any iron surface 360 mini digital protractor is designed for setting or checking relative angles between surfaces, also working as true digital level for tight spots Digital electronic level can quickly and easily attach to aw tables, fences, blades and other metallic surfaces The digital angle finder is small and light, making it convenient to carry and used Digital angle gauge can be Clearly and Easily Read on the LCD Display