THIS R&K TOOL UNEF THREAD RING GAUGE 2A IS PROVIDED AS A SET OF TWO PIECES. THE GAUGE IS SPECIFIED FOR A SIZE OF 1-5/8”-18 AND HAS A THICKNESS OF .81”. THE TECHNICAL DIMENSIONS INCLUDE A GO PITCH DIAMETER (GOPD) OF 1.5874 AND A NO GO PITCH DIAMETER (NO GOPD) OF 1.5824.