【Economical Measuring Tool】This Pipe Marker Centering Tool is efficient and useful for setting center lines, determining angles and marks for butt-ins and locating points inside pipes or tanks, arranging keyways and calculating declivity. It can measure tanks or pipes with a diameter of at least 1/2" or larger.【Easy to Operate】Step1.Loosen or tighten the hexagonal nut with the included hex key allen wrench. Step2.Place the pipe marker tool on the pipe and find the angle you want. Step3.Push the center column down to the fixed point position. Step4.Tap with a hammer to leave a fixed point mark on the pipe.【Durable and Sturdy Material】The pipe fitter tool can wrap around the circumference of pipes to measure and mark, and it is made of a highly flexible, heat-resistant gasket material. This Pipe Center Finder Tool is easy to use for pipe fitters and welders as a must have tool.【Y-Head Shape Base with a DSL】This safety pipe center finder has a 4 inch Y-type base fitted with an adjustable dial bubble protractor (DSL). You could push the center column down to the fixed point position as you want. It is a must have on your list of pipe welding tools.【Adjustable Dial Bubble Protractor】Printed with a scale in inches, an inch chart and tangent chart, this pipefitter tool can help you make straight lines around pipes. When judging the horizontal state, the bubble of the green liquid needs to be in the middle of two lines on the protractor. 【Note:】When determining the angle, the bubble of the green liquid should be in the horizontal position whatever the angle is. Product Description TO MEASURE PIPES AND TANKS THAT 5" IN DIAMETER OR LARGER · Used for setting center lines · Establishing angles /marks for butt-ins · Locating points inside pipes/tanks Judge the horizontal state： Bubble of green liquid needs to be in the middle of these two lines to determine. Note: When determining the angle, the green bubble should be in the horizontal position whatever the angle is. Easy to Use Loosen/tighten the hexagonal nut with the included hex key allen wrench. Place on the pipe and find the angle you want after loosening the hexagonal nut. Push the center column down to the fixed point position with a small hammer or mallet to operate the hardened centering pin. Built-in adjustable “DIAL BUBBLE PROTRACTOR" (DSL) 4 " Y-TYPE Base conforms to pipe curvature Heavy duty and durable for longtime use.