Battery Holder for 18650 batteries
The 18650 batteries looks like bigger A/LR6 battery but they contains quite more power into a "more standard" format. This kind of battery also offers some mechanical protection around the earth of the battery (remind that Lipo/LiOn based battery are very sensitive to mechanical accidents).
This holder would be welcome if you need some 18650 power for your project. Quick and easy to connect, the battery holder do have 24 AWG wires allowing to transport a nominal current of 2 A max. If you need more current then it will be necessary to solder bigger wires.