Manufactured by Tinker & Rasor the Model 45/90 is an audio locator handheld probe for use with Model PD Mark IV receiver. The addition of the 45/90 Probe to the Model PD Pipe/Cable/Short Locator kit gives the operator a search coil much closer to the ground, saving the back strain of bending over on difficult locates. The 45/90 also makes depth determination much easier.