Shadow Devices were an example of Shadow Technology that was created by the Haydonites. They functioned by creating what was termed as a shadow dimensional field around targets that masked their reflex furnaces and made them invisible to the Invid's Protoculture sensors.
The Haydonites provided Shadow Devices to Admiral Rick Hunter's Robotech Expeditionary Force to assist them in the war against the Invid. All the technical details for this Shadow technology was given through the android Janice Em on the condition that the secrecy of the Haydonites' involvement was maintained. Shadow devices provided an excellent advantage to the Robotech forces as they were invisible to the Invid sensors. Ultimately, the Third Robotech War ended with the Earth freed after the Regess departed the planet in peace.
Despite this unexpected development, The Awareness commanded the Haydonites to proceed with their objective of eliminating all races that made use of the Flower of Life as a power source. Striking at Space Station Liberty, the Haydonites used their knowledge of Shadow technology to cause the Shadow Devices and Synchro cannons to overload whereupon they exploded, thus destroying the REF vessels carrying them. After discovering this, Captain Vince Grant ordered his troops to abandon their Shadow fighters in favor of non-Shadow tech craft as they were at a severe disadvantage against the Haydonites.