Inventory

Your inventory is the "place" where all items that your character has are stored.

Fallout, Fallout 2 and Fallout Tactics
Access it by pushing the "i" key during the game. In the inventory you can change the armor you wear, use food and drugs, load/unload weapons you have, and change your two active weapons.

During the battle access to inventory costs 4 action points, but can be reduced by perk Quick Pockets. In Fallout Tactics, access to the inventory is free, but various actions in the inventory cost you action points and the vehicles also have inventories.

Fallout 3 and Fallout: New Vegas
Access it by pushing the default button "tab" for PC during the game, B on Xbox 360 and O on PS3. Access to the inventory is free during a fight and freeze the game until you close the inventory.

The items are sorted into weapons, armor, aid, misc., and ammo categories. In the inventory you can change your weapon in hand, the armor you wear and use food and drugs. In Fallout: New Vegas, you can also put a weapon mod in a weapon and change ammo of your weapon in hand.

Fallout: Brotherhood of Steel
Access it by pushing the "select" button for PS2 during the game. Access to the inventory is free during a fight and freeze the game until you close the inventory.

The items are sorted into weapons, armor, items. In the inventory you can change your three active weapons, the armor you wear and use drugs.