Effortlessly Find Pipe Centers:This tool is perfect for pipefitters and welders to set center lines, determine angles, locate points inside pipes or tanks, mark butt-ins, and more. It can measure tanks or pipes with a diameter of at least 1/2" or larger, Perfect for pipe fitters and welders Easy to Use:Simply loosen or tighten the hexagonal nut, place the tool on the pipe, and tap with a hammer to leave a fixed point mark on the pipe. With just a few simple steps, you can use this pipe marker tool to find the angle you want and leave a fixed point mark on the pipe Adjustable Dial Bubble Protractor:The 4 inch Y-type head is fitted with an adjustable dial bubble protractor (DSL) protractor for enhanced precision, ensuring accurate measurements every time Durable and Sturdy Material:Made of highly flexible material and High-quality metal raw materials, this pipe fitter tool is built to last. Easily measure around pipes, making it a reliable tool for repair pipe work Operation steps:1. Use the included hex wrench to loosen or tighten the hex nut.2. Place the pipeline marking tool on the pipeline and find the desired angle.3. Push the center pillar downwards to the fixed point position.4. Use a hammer to strike and leave a fixed point mark on the pipeline