The declination body unit allows you to expand the AP Photoguider to a complete equatorial AP mount with mototized RA and DC axes. You can move and track the mount in both axes. In addition, you will need the Manual Fine Adjustment Module , or the DEC motor module , as well as the AP counterweight rod and a counterweight. The counter weights of the SX mount series can all be used on the counter weight rod. The APZ counter weight can also be attached to this unit. The built-in battery compartment serves as an additional power supply and is powered by 4 AA batteries.