Western Instruments W-PT Pull Test Bars are used to verify the performance of a Yoke.  Each W-PT is traceable to NIST, and supplied with a Certificate of Compliance to; ASTM-E1444; E709; and ASME Section V, Article 7.  Each Bar is equipped with; a Machined Groove, to ensure the Yoke Legs are centered laterally; a hole in the center to permit multiple bars to be fastened together; as well as a Serial Number for tractability.  Furthermore each bar has a Pole Spacing Scale (Imperial and Metric) affixed to one side, as most specifications now include Pole Distance and Weight for Calibrating Yokes.