Abstract: To assist in locating an underground or otherwise hidden non-electrically-conducting plastic pipe carrying a fluid such as heating gas a tool is provided which comprises a reel of relatively stiff but flexible locator wire, a hermetically-sealing first bushing through which the locator wire passes and a coupler for engaging a pipe exposed to view but coupled to and communicating for fluid flow with the pipe to be located, such coupler being adapted to receive, in snug fashion, said first bushing and including a packing membrane through which said locator wire passes to further assure no loss of fluid from the pipe being located, said locator terminating at its extremity remote from the reel in a guide member having a shape which may be described as suggestive of an oblate spheroid; i.e.