Replace your Garmin Nuvi 42 Battery or Keep an Extra Battery on hand as a backup. This is an Extended Capacity 1100 mAh, Lithium-Ion Battery that offers even more up time than your original. Works in your Garmin Nuvi 42 GPS. Simple, Easy and Inexpensive! You get a New Battery, Special Tools Necessary for Battery Installation, helpful Video Instructions, AND You also get a full ONE YEAR Money Back Guarantee exclusively when you purchase from us!