Short Light String:

This light string has the lights close together with different color LEDs inside colored 1x1 round plates with 1x1 clips.  Each end has a plug meaning you can add other lights to this light string

Long Light String:

This light string has the lights a little further spread apart.  It has RGB LEDs inside of clear 1x1 round bricks.  Each end has a plug meaning you can add other lights to this light string.