The PCWI COIL910 Circular Pipeline Coil Electrode 36" / 910mm Diameter # 0197 CPCE-0197 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.