If there's a button that says 'Use' below the item in the Inventory, you can use it – otherwise the items will be used automatically for upgrading your structures and units. Combat Bonuses are the exception: they won't be applied in the battle automatically, you will have to select them for use yourself in the menu that opens up after clicking on the Radio icon.
Combat Bonuses are sold in the Shop and obtained with the daily bonus for launching the game a few days in a row. Items used for upgrades can be produced in the Laboratory or the Assembly Plant, obtained when collecting the resources or in a combat with another player. On occasions you can find free item give-aways at the official app page.
Bonuses purchased in the Shop:
- Medi-Kit Drop restores 3 points of health for a single unit.
- Evac brings the rest of your troops home safe and sound.
- Predator Missiles bring 8 points of damage to a single ground-based target.
- Airstrike brings 5 points of damage to a single ground-based target.
- Mosquito Missiles bring 2 points of damage to a single ground-based target.
- Maximum Energy refills your energy to the max level.
- Adrenaline Container replenishes 5 points of Adrenaline.
- Adrenaline Can replenishes 10 points of Adrenaline.
You can also purchase sets of the above Bonuses in the Shop, e.g. "10 "Mosquito" Missiles" or "3 Medi-kits". To use them in combat you need to "unwrap" the set first: find it in the inventory and click "Use" — the set will disappear leaving the appropriate number of the Bonuses.
Items obtained in combat:
- Iridium can be found in destroyed enemy Ore Mines; there is also a chance you get an Iridium while extracting iron at your own Ore Mines.
- Engine and Weapon Parts are obtained from destroyed enemy vehicles after you perform a successful attack on an enemy base.
- Intelligence is obtained for each successfully completed attack against an enemy base, no matter how many stars you've been able to get.
- Enemy Technologies can only be gained in action, from a destroyed enemy HQ, an Academy or a Research Center.
- Killer Shell and Armor Vest are obtained from killed enemy infantry after you perform a successful attack on an enemy base.
Please note, that these items drop randomly, which means that there is a low chance to obtain them, e.g. you won't get an Engine or Weapon Parts from every destroyed enemy vehicle.
Items produced in the Laboratory:
- Chemical — 110 coins and 75 oil.
- Ferrite — 145 coins and 18 iron.
- Elirium — 880 coins and 680 oil.
- Cryo Alloy — 1050 coins and 95 iron.
- Energon — 5 x Chemical, 2 x Elirium, 2050 coins and 1650 oil.
- Ethernium — 1 x Elirium, 4 x Cryo Alloy, 2210 coins and 245 iron.
Items produced at the Assembly Plant:
- Fuel Mix — 2250 coins, 600 oil and 2 x Energon.
- Superalloy — 2600 coins, 110 iron and 2 x Ethernium.
- Killer Missile — 3500 coins, 1025 oil, 2 x Energon, 2 x Iridium and 1 x Intelligence.
- Armor Plate — 4100 coins, 440 oil, 2 x Ethernium, 2 x Iridium and 1 x Intelligence.
- Turbine — 660 coins, 2 x Engine, 4 x Iridium, 3 x Intelligence and 1 x Enemy Technologies.
- Gun — 7600 coins, 2 x Weapon Parts, 4 x Enemy Technologies, 6 x Engine and 2 x Intelligence.