The woods can be dark at night. So dark you don't want find yourself rifling through your bag for spare batteries for your Rino 600-Series handheld GPS radio. And once you find them, it'll be difficult to get them into the Rino's battery compartment correctly without some light. This alkaline battery pack lets you pre-load 4 spare "AA" batteries (not included) into a spare battery compartment so they're ready to go when your Rino loses power. All you have to do is slide off the old battery pack, slap this spare pack into your Rino, and you'll be fully charged again.