A magneto-strictive scanning unit is formed through an actuation pushrod disposed and guided on an outside of a tight housing of a position sensor, in which the delicate sensor is tightly encapsulated, and components of an actuation unit can be disassembled and repaired without opening the sensor housing. The tee placement end includes a retaining assembly that automatically releases the golf tee upon insertion of the tee into the ground. The stem fits slidingly in the interior space of the hollow rod and is formed with a slot that is aligned with the slot in the hollow rod.