Portable: The goniometer tool adopts sliding and retractable design, which reduces the occupied space and is easy to carry and store when not in use. Multi-precise measurement -angle: this goniometer can accurately measure the angle between 10 degrees and 170 degrees, can measure the angle and the half-angle included at the same time, lock the angle L, and can also divide the angle perfectly. Easy to use: place it on the work area, slide the ruler into the desired shape and tighten the screw. There you can make perfect measurements and now you can transfer and track them on any material. Wide Use: This protractor works with tile, brick, stone, wood, cut laminate and any project you can think of. Perfect for any DIY enthusiast and carpenter. Product Material: This protractor is made of high quality aluminum alloy, which is superior and stronger than traditional plastic protractors; it is scratch resistant and very durable.