"GAGE,CONCENTRICITY;USED TO VERIFY THE CONCENTRICITY OF THE FUEL SLINGER AND LABYRINTH BALANCE ASSY TO THE H.P. TURBINE SHAFT AFTER THEY HAVE BEEN ASEMBLIED;ITEM IS MADE OF HARDENED PLAIN CARBON STEEL WITH NATURAL FINISH,IS APPROXIMATELY 5 IN. LONG, 1 1/2 IN. DIAMETER, AND WEIGHTS APPROXIMATELY 3/4 POUND"