This hardened stainless steel calipers is a great tool for measuring the inside, outside or depth of an object up to 150mm with a resolution of 0.01mm. Can be turned on and off using a button. The five-digit LCD makes is easy to read the measured size and can be tared using a button. The caliper comes with two 1.5V batteries. To measure 3D filament, put in the filament at an angle and don't press too hard.