With the SparkFun COM-11705 plug your power supply into one end and the other into your project and, just like that, you've got a power switch!
The on-off rocker switch has a good stiff 'click' to it, so it isn't easy to accidentally switch. It's also fairly small so it won't add too much unnecessary bulk to your project.
Dimensions:
- Switch Body: ≈ 61 x 27 x 23mm
- Cable: 85mm long (each side)
- Barrel Connector: 5.5x2.1mm