The Haltec Large Bore Swivel Gauge is a precision measuring instrument used to measure the inside diameter of pipes, tubes, and holes. It has a measurement range of 1-1/4" to 6" diameter. The gauge features a hardened, ground spindle with a carbide measuring ball on the end. It has a dial indicator with .001" graduations for precise measurements. The swivel head design allows positioning at any angle. It can be used to measure ID dimensions in machining, welding, or tube bending applications. The gauge is made in the USA and comes with a vinyl storage case.