Replace your Magellan GPS Battery (T300-3) or Keep an Extra Battery on hand as a backup. This is an Extended Capacity 750 mAh, Lithium-Ion Battery that offers up even more up time than your original. Works in many Magellan GPS models. Simple, Easy and Inexpensive! You get a New Battery, an Installation Video, a FREE Torx and Shim Tool (necessary for installation), AND You also get a full ONE YEAR Money Back Guarantee exclusively when you purchase from us!