the Garmin Lithium-Ion Battery Pack for Rino 520 is a replacement battery that provides mobile power to your Garmin Rino Series GPS unit. This battery pack is an exact replacement for the one that comes with the unit. The Garmin battery pack has a high capacity 8.4 volt 2400 mAh Lithium-Ion battery that typically provides up to 16 hours of power for your GPS and weighs approximately 119 grams.