Great for any low-voltage, small to medium-current device, the JST connector has become a standard in many small models for battery and other connections. An easy way to add a "switch" to anything in or on your model, they are easy to grip, and light enough that they do not add excessive weight.  Pigtails are about 6" long, and are available in two wire sizes, 22AWG (smaller) and 18AWG (larger).  Both are made with very flexible silicone wire, and come with ends that are pre-stripped and tinned.
 
Sold in pairs, 1-male, 1-female.  Also available in sets of 5 pairs