Easy to use his tube center finder has a 4-inch Y-shaped base with an adjustable bubble protractors You can push the center post down to the anchors point as needed a must-have in your list of pipe welding tools Printed with inch scale, inch chart and tangents chart, this pipe installation tool can draw straight lines around pipes To judge, bubble of the green liquid needs to be halfway between the two lines on the protractors The pipe installation tool can be wrap around the circumference of the pipe for measuring and marking, it is highly flexible, gaskets This pipe center finder tool is easy to use and is a must-have for pipe fitters and welders This pipe marking centering tool is very effective and useful for setting center, determining angles and marks for butt joints, and locating point within pipes or tanks, arranging, and calculating It can measure tanks or pipes that are at least 1 / 2inch in diameter or larger, Manufacturer: XAGMODSHN