If you feel the need to protect the future of your family by purchasing gold or silver coins, then you need to buy coins that are not valued by numismatics. You need to buy coins that are valued by weight and recognizable standard value.
That said before you buy the batteries it is better to know what kind of battery is suited for the equipment that you have. Generally all the manufactures include this advice on the equipment itself. CR2032 lithium price are also such batteries which are used in a lot of equipments. The other most common type of batteries is the alkaline batteries and the nickel cadmium batteries.
GPS stands for Global Positioning System. That is a fancy term that tells you exactly where you happen to be. Sort of like those fantastic maps cobalt mining canada within the malls which have a dot that states You Are Here". It does this by talking with government satellites. You will find over 24 of them, but the GPS only requires 3 to be able to discover your place. It does this by triangulation (Am I becoming way too technical?) Today's GPS, if Wide Area Augmentation System (WAAS) capable, can calculate your place to within 3 meters (about 10 feet), but do not depend on that sort of accuracy. The GPS ought to be in a position to establish your place to 30 feet or even less.
Cordless Drills have different power ratings. The least powerful ones are very compact in size. The next size up have more power and are used for general projects. Then there's the super powerful ones that's big and specialized. The different power ratings of the tool are meant to do different type of projects. If you use a highly powerful one to do a dandy job of fastening tiny little screws of a delicate jewelry box, then clearly the tool isn't the best one.
A lithium drill is much lighter than a comparable drill of the same voltage. This allows you to use higher voltage tools with lighter weight. Remember, voltage equals power, mah equals the gas tank of the battery. So, if you are using a 12 volt now, a 18 volt or even a 36 volt lithium mines ontario drill will offer you much more power and still have the same run time of you 12 volt with close to the same weight.
Never discharge your LiPo cells to less than 3.3volts per cell, not the total pack voltage. Most ESC's today will do a soft cut-off at 3.3volts per cell and a hard cut-off at 3.0volts per cell. However some will not give you and warning. Best advice is to fly with a timer and monitor the voltage and adjust your flying time if needs be.
You cannot go wrong with this type of plan. In the end, if the world is OK, you still have your gold and silver, you just may have missed out on the next dot com bubble.