The PCWI COIL600 Circular Pipeline Coil Electrode 24" / 600mm Diameter # 0191 CPCE-0191 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.