The suit has a similar design to the assassin suit, but is cleaner and has a luminescent white chest piece with similar white stripes on the back, possibly circuitry. The suit itself has a built-in medical system that automatically dispenses Med-X and stimpaks, similar to the prototype medic power armor in Fallout 3. A female on-board computer narrates the usage and current levels of these items, as well as warning of impending combat situations, reminding the Courier of an active Pip-Boy light, and making off-hand comments without prompting. The computer is very similar to, and just as talkative as, the personality modules given to the Light Switches in The Sink.
When poisoned by a cazador, the suit will dispense a stimpak if available and cure the poison.
When the Courier is crippled while wearing the suit, the suit will dispense Med-X.
The suit can be upgraded in the course of four stealth tests in the X-13 facility. Bonuses from upgrades are cumulative.
- Firmware version 1.1 - Has a bonus of +10 to Sneak (Stacks with the +15 Sneak already on the armor, giving +25 to Sneak).
- Firmware version 1.2 - Adds a bonus of +1 Perception.
- Firmware version 1.3 - Adds a bonus of +1 Agility.
- Firmware version 1.4 - Adds a bonus of +20% to Stealth movement speed.
|Combat armor||15||25||400||6500||Medium armor||None|
|Chinese stealth armor||12||20||100||500||Light armor||+5 Sneak|
|Assassin suit||14||20||500||7500||Light armor||+10 Sneak|
|Stealth suit Mk II||14||25||500||7500||Medium armor|| All of the effects stack:|
Sneak +15 (Firmware v1.0)
Sneak +10 (Firmware v1.1)
Perception +1 (Firmware v1.2)
Agility +1 (Firmware v1.3)
Movement-speed while crouched +20% (Firmware v1.4)
- It is found in three pieces in the X-13 research facility. One part in each of the three labs in the first hallway the player character comes to after entering the facility.
- The research for the suit went under the name of Project: Blue Blood. 
- It appears that the creation of this suit was based on the Chinese stealth armor. This can be seen in the X-13 testing facility when one looks at the mannequins wearing the prototypes. However, while the head piece is seen on the mannequins, there is no head piece attached to the suit or as a separate item.
- Unlike the prototype medic power armor from Fallout 3, the Med-X dispensed by the suit is regular Med-X, which the player can become addicted to.
- Stimpaks used by the suit are not affected by Medicine level.
- The suit will be sure to mention any time the player character is sneaking with the Pip-Boy light on.
- In Normal mode, if the player character's health is low, the suit will continuously administer stimpaks until their health reaches an adequate level. In Hardcore mode, the suit checks to see if there are any restore health effects first; if not, it will administer a stimpak.
- When unequipping the suit from a companion, it still plays an audio comment as if the player was wearing it.
- Sometimes if the player character dies, the suit can be heard desperately trying to pump stimpaks in order to keep the Courier alive, to no avail.
- If the Courier kills the Robobrains within the facility, the suit may comment on this, stating "That's a shame. Normally, those units would help defend the facility in case of an attack".
- The computer for this suit tends to be sarcastic, notably when turning on the Pip-Boy light when sneaking, and has a mischievous side [e.g. claiming it is time for combat even if there are no (more) enemies]. This is shared to a certain extent with Raul Tejada.
- Sometimes, the computer will ask the Courier, "Do you like me?"
- "Hello. It's nice to meet you. Who can I hide you from today?"
- "We're okay on Med-X. Until we have to numb the pain."
- "We're okay on Stimpaks."
- "Will you love me if I help you hide?"
- "We're all lit up. Is it Christmas?"
- "You're my best friend forever."
- "Did you even know you were wearing me?"
- "Please take this. I don't want you to die."
- "We haven't seen anybody in a while... maybe the monsters have stealth suits too."
- "Technically, it's impossible to overdose on painkillers."
- "Don't you like me any more?"
- "No more Med-X to kill the pain."
- "Sneaking done. Fighting now."
- "Who do you think is cuter, Dr. Klein or Dr. Borous?"
- "Psst. If you hack the mines this will go lots faster."
- "Stealth Boys are a robot's big weakness."
- "We're out of Stimpaks. Maybe you'd be better off with an Auto-Doc suit...."
- "Nobody ever notices me... but they notice the Pip-Boy light."
- "Have you ever wanted to be invisible?"
Behind the scenes
- PC There is a bug where after the suit auto-applies a stimpak your health will not increase; keeping your health at the minimum threshold for the damage script. This causes the suit to use a stimpak every time you're injured, as you drop below the scripted HP, burning through stimpaks extremely quickly. [verified]
- PC Before starting the stealth research in X-13 make sure all armor pieces are in your inventory. Starting the run before the pieces are taken may bug the script and result in not getting the armor. [verified]
- PC The stealth suit seems to occasionally glitch out, and continuously issue doses of Med-X until the user's supply has been emptied, or until the suit is taken off (Leading to Med-X addiction very quickly). [verified]
- PC When fully upgraded, it doesn't boost your sneak speed by the said 20%. [verified]
- Xbox 360 In third-person view, rotating to the front side of your character can sometimes cause the head and arms of the player character to disappear, immediately reappearing once the camera returns to the rear. [verified]