Minelab F3 Mine Detector Operation Manual page 14

 Holding the detector with the coil pointing toward the ground,
open the Middle Camlock and extend the Lower Shaft to the
desired length. Lock the Lower Shaft into position by closing the
Middle Camlock.
The Lower Shaft must be extended at least 100mm (4ins). Incorrect
operation of the detector may result if the detector is used with the
Lower Shaft fully retracted.
 Open the Upper Camlock and extend the Middle Shaft to the
desired length. Lock the Middle Shaft into position by closing the
Upper Camlock.
h. Undo the dustcaps from the Earset plug and Earset socket on the
detector. As shown in Figure 8, gently hold the Earset by the
rubber collar using thumb and index finger (raised double arrow
should be uppermost). Align the plug with the Earset socket and
firmly slide the collar onto the socket. Confirm the plug is locked
into position by gently pulling back on the rubber collar.
Figure 7: Camlock Locations
NOTE
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