(1) The disconnectable, rubber [[insulation]]-covered downhole end of a [[survey cable]] on which current and measure electrodes (cable electrodes) are mounted for [[resistivity]] measuring electrode configurations requiring longer spacings than can be attained on a [[sonde]]. The [[head]], to which the sonde is attached, is an integral part of the [[fishing bell]] and bridle.

(2) For those services which do not require bridle electrodes, it is the short disconnectable length of cable on which the fishing bell and head are attached. The disconnectable feature permits the quick changing of head types and sizes, and easier servicing.