A range of rolling spring electrodes catering for virtually all pipe work diameters can be supplied along with or as spare  for holiday detectors. Simple connection allows spring to be easily fitted around pipe work. The connector assembly can be screws into the high voltage probe handle of holiday detector.. The rolling spring can be easily moved along the pipe work ensuring that the pipe work coating is comprehensively tested for holidays. Holiday detector’s external spring electrodes are essential tool for pipeline contractors during installation of coated pipelines. External spring electrodes are also called rolling rings. We also provide internal conductive electrodes for inspection of thin coating inside the pipe.