The 512Hz Locating Sonde and Adapter Kit works with a duct rodder to trace underground pipes and conduit. The kit includes the #14-170 Sonde and #9-169 Flexible Chain Adapter. The flexible adapter is used to attach the sonde to the end of a rodder with 3/8"-16 thread (Good Buddy, Big Buddy and 5/16"/7/16" Duct Hunters). The sonde emits a radio signal allowing you to locate the end of the rod in a pipe or duct using a handheld receiver.