Save money by using rechargeable NiMh (Nickel Metal Hrdride) batteries in your GPS. These batteries pay for themselves very quickly; are good for the environment as you stop throwing away disposable batteries; are reliable and have no 'memory' unlike their older counterpart the NiCad battery. With NiMh batteries you can recharge them in any state and they will retain their full charge, you don't have to fully discharge them before charging and this makes them ideal for geocaching and GPS users.