Like my recent AA/AAA battery holder for when we travel this is for NB-5L's. The new Canon S100 (not to be confused with the old Canon S100) is a bit of a power hog so when traveling you need more than one battery, sometimes more than two batteries.
However after one battery they start to become hard to control in your pockets, purses, book bags, etc.
So this is parametric in that you can say how many batteries you want it to hold and the size and shape of each battery.
Tolerances are pretty tight so some fiddling may be in order.
Print... make sure your batteries fit... put batteries in.. put in pocket... take pictures knowing you will be able to find your batteries when you need them.
We also use a convention for knowing if a battery is charged: If the battery terminals are visible (i.e.: facing 'up') then the battery is charged.