|“||Mechanized Exoskeletal Cybersuits, or MECs, are powerful battlesuits that mount an array of useful weaponry and support equipment. Each MEC can be customized to fit specific tactical approaches. If a MEC Trooper dies, his MEC can be recovered and repaired in the Cybernetics Lab.||”|
– XCOM Database, XCOM: Enemy Within
MEC Suits grant MEC Troopers the Hardened trait plus immunities to fire and poison, but can be damaged in battle and require repairs. MECs can't use cover and can be armed with a Minigun, Railgun or Particle Cannon.
Production Specifications & Tactical Info
MECs are produced and upgraded in the Cybernetics Lab. MECs are built and upgraded immediately upon purchase and can be advanced through three tiers. Each of the tiers has a different name, bonus stats and a different selection of Tactical Subsystems; Tactical Subsystems stack with those from previous tiers for a total of three available on any given MEC.
|Kinetic Strike Module||A powerful arm upgrade for the MEC, allowing the wielder to pulverize adjacent cover and enemies. Also boosts mobility.
A 12 damage melee attack that can also be used to directly destroy cover; can be upgraded with the MEC Close Combat Foundry project to 18 melee damage and won't end the MEC's turn if it was used for the first action. It also gives a +2 tiles bonus to movement distance.
|Flamethrower||Allows MEC to lay waste to a cone-shaped area. Flame can spill outside the aiming area.
Does 6 fire damage to units in the damage cone, and fire spills into extra tiles at cone's edge. Sets fire to the environment and causes enemies to panic. Can be upgraded with the Jellied Elerium Foundry project to 9 fire damage.
Prerequisites: UFO Power Source research
Upgrade Cost: §29, 60, 10 Engineers
Stat Bonuses: +12 Armor Health, +10 Defense, +15 Will
A MEC-2 may add one of the following two Tactical Subsystems:
|Grenade Launcher||MECs can make for their lack of thrown grenade capability with a long-range grenade launcher.
Deals 4 damage in a 3.5 tile blast range. Automatically upgraded to 5 damage after completing the Alien Grenades Foundry project.
|Restorative Mist||Medikits require fine motor control; instead, the MEC can spray Restorative Mist to heal all nearby allies.
Restores 4 health to injured allies within 3.5 tiles from the MEC, but cannot stabilize or revive fallen allies. Automatically upgraded to restore 6 Health after completing the Improved Medikit Foundry Project.
MEC-3 Paladin 
Prerequisites: Titan Armor research
Upgrade Cost: §110, 100, 25 Engineers
Stat Bonuses: +16 Armor Health, +10 Defense, +20 Will
A MEC-3 may further add one of the following two Tactical Subsystems:
|Proximity Mine Launcher||Proximity mines can be deployed at medium range, and will await nearby enemy movement before triggering their explosive charges.
Each mine deals 8 explosive damage and is triggered by enemies who move within or through its 2 tile radius; isn't triggered by your units. Mines can also be triggered by explosions; either through grenades, rockets, or exploding vehicles and units.
|Electro Pulse||MECs can stun robotic enemies and damage organic ones with this area-of-effect electric shock device.
Deals 5 damage to all units within 4 tiles of the MEC and disables robotic units for a turn.
In certain game versions, when you do not have enough resources to build or upgrade a MEC, the MEC Bay might give you a grey text saying you have not met all the previous research requirements.
MEC's are tough, but not by any means invincible. Sustained Plasma fire from heavy - hitting aliens such as Muton Elites will still bring them down.