http://cnflin.en.alibaba.com/product/371066000-212471709/KCD5_304_ON_OFF_line_wire_switch_lamp_parts.html
This inline switch is great when you just want a simple on/off toggle switch that's already enclosed. Inside is a simple rocker switch with solder terminals with crimp strain relief. Attach some wires, solder them in place, and press-fit the enclosure together and you have a clean-looking switch.