 "Garmin Li-Ion Battery Pack (010-11654-03)" (010-11654-03) from Solid Signal"
"Stay on the right path longer and while away from a regular power source with the Garmin 010-11654-03 Li-Ion Battery Pack. Using this product, you can extend your GPS devices battery life by up to several hours. This Garmin battery pack is compatible with the Montana, so you can plan a long hike or outdoor excursion with plenty of confidence." 
 "Garmin Montana Lithium-Ion Battery Pack"@en Pack | Sportsman's Warehouse"@en
"Garmin Montana Lithium-Ion Battery Pack- replacement rechargeable battery pack for your Montana.  Don't run out of power!"@en 