IETs have unnaturally pale skin and red eyes hidden behind goggles (the red is still visible through the goggles, however). This is caused by the physiopharmaceutical augmentation process. Because of this, they wear goggles and dark clothing to diminish the albino appearance. Their voice sounds robotic because they also have an integrated rebreather in their bronchus, and unlike MiBs created in the past by Majestic 12, it gives full resistance to poison and gas attacks. Like MiBs, IETs have the symbol of Illuminati (image of an eye) tattooed on the back of their necks.
IETs have improved capabilities thanks to pharmaceuticals, with addition of physical and psychological conditioning like MiBs. Their strength and endurance are greatly improved. They are the second type of physiopharmaceutically augmented individuals and successors of the Majestic 12 MiB program.
They possess the ability to cloak when entering combat, indicating that they have either been augmented with a version of the cloak biomod, or are equipped with an improved variation of Thermoptic camo.
Like their earlier counterparts, they also use a self-termination mechanism upon death that causes their bodies to dissolve in a massive cloud of toxic gas that quickly kills anyone within a radius of 5 meters. This eliminates any evidence of the agent and may damage the killer as well. Unlike the MiBs, the IETs can't be knocked out as the termination mechanism is also triggered if an IET falls unconscious.
IETs are comparatively less resilient than MIBs were; they are only about 50% more durable than a regular combatant, while MIBs were 4 times as durable as a standard opponent. However, their combat effectiveness is still superior to regular troops, in addition to their ability to cloak and immunity to poison gas.