5Battery InstallationThe GPS II operates on 4 AA batteries, which are installed at the base of theunit. Normal battery life is approximately 15 hours, and up to 20 hours when theunit is in battery saver mode.To install the batteries:1. Flip up the metal ring at the base of the unit, and turn the ring 90 degrees counterclockwise.2. Install the batteries (Fig. 5), and close the battery compartment door.3. Lock the door in the closed position by rotating the metal ring 90 degreesclockwise.Battery life varies due to a variety of factors, including temperature,backlighting, and whether the unit is in battery saver mode. You may findthat you get more or less battery life in different conditions.When replacing the GPS II’s batteries, observe the polaritymarkings engraved in the plastic case.READ ME FIRST!PolarityMarkingsFig. 5