Meba 20 Inches Stainless Steel Digital Angle Ruler Goniometerangle Finder Rulerangle Ruler Definitionruler Angle Digital stainless steel ruler and angle finder combo makes precise measurements for easy woodworking Digital protractor has lock and reverse angle functions that make all types of work easy and fast Hinge mechanism on the angle rule allows a full 360-degrees to measure inside outside and reverse an Woodworking tool can be zeroed at any point in the swing; digital measuring stick has a length of 5 Battery 3V included