The PCWI COIL250 Circular Pipeline Coil Electrode 10" / 250mm Diameter # 0184 CPCE-0184 is ideal for verification of porosity or holidays on pipelines or circular surfaces. This PCWI circular Pipeline Coil is suitable for all High Voltage Porosity detectors, holiday detectors, spark testers and jeepers. The coil electrodes are shipped complete with ball bearing ends.