[Digital Goniometer] A perforated digital goniometer for hanging a digital protractor, designed for industrial applications involving precise angle adjustment, such as alcoves and cabins, sloping roofs, and running handrails (Note: this is not a digital level). [Retro LCD Screen] Backlit for easy reading, you can clearly see the data even in low-light conditions. [High Precision] Measuring accuracy ± 0.5 °, increase/decrease increment: 0.1 °, corner angle 0-225 °, allowing you to accurately measure the angle horizontally and vertically. [Mechanical Locking] Features a locking knob to keep the angle unchanged during the line process, and a hold button to lock the angle. [Battery Powered] Powered by a 9-Volt battery (included) and automatically shuts off after 5 minutes of inactivity to extend battery life. Warning: Do not move the screws and components randomly. Handle your angle indicator carefully, use a constant force to rotate the rotating arm, and do not use excessive force. Do not leave the backlight on for too long. When the low power icon appears on the screen, replace the batteries.