The Quick Connect Couplers are designed to allow the user to quickly connect or disconnect two non-character lightsabers, which provides a quick way to go from a double-bladed staff lightsaber to being two lightsabers.
 
To connect two lightsabers together, push the textured grip section into the coupler while pulling down on the middle spring section.
 
To disconnect two lightsabers from each other, pull down on the textured grip section.
 
Keep in mind, from use, you may need to gently twist or wiggle the other side if it gets stuck, to help the bearings fall out of the groove to help release the coupler.