The CLE-004 was a repulsorlift-equipped droid with a single electrostatic polisher protruding on an articulated arm from its squat body. The droid used this to clear windows of grime, dirt and digit marks left by installation droids. The CLE-004 unit could polish even a large window in a matter of seconds. Although they commonly accompanied INS-444 droids to ensure newly-installed windows were spotless, CLE-004 droids were often seen working alone on worlds such as Coruscant. Their repulsors allowed them to reach even the tallest buildings in Galactic City. These droids did not have an internal processor, instead relying on a master control system to broadcast commands to their top-mounted power receivers.
CLE-004 droids were a common sight outside an office or apartment window, and this familiar presence was sometimes used to turn the droids into hovering spies. Their presence unnoticed, CLE-004 units modified to hold eavesdropping devices or holorecorders could easily transmit activities within any given building back to various crime bosses, news organizations or jilted lovers looking to catch their partners in the act.