Need to add more voltage to your regular 4AA battery pack? Parallax has come up with this ingenious plug in module that adds a 5th module to your AA quad-pack holder.
The BOE-Boost module is one of those "Gee, why didn't we think of this?!?" sort of products.
When using a 4xAA cell holder, you get 6V when using alkaline (Duracell/Energizer style) batteries. If you try to use a rechargeable, you will only get a nominal 4.8V instead of 6V, which can cause some problems with devices expecting a full 6V. Enter the BOE-Boost!
The BOE-Boost nestles on top of the battery pack, and the tabs intercept the power flow to add a 5th AA cell in series with the rest. So now you have 5 AA rechargeables, giving a solid 6 volts! Or if you wish, you can use all alkaline cells, and feed 7.5V to what would be 6V system. Now, where would you want to do that? Oh, say if you want to run your robot a bit faster than usual. Or you want your device to run longer before the batteries give out (assuming it can accommodate the extra voltage).
It simply snaps into place on the top of a BOE-Bot 4AA cell holder - no tools needed, and is easily removed!