Lockbox

A lockbox is a container which holds credits, armor, weapons, or consumables. They are classified with a number from 1 to 6 and an Item Roll Level. The class and level indicates the number of credits and level of items within a lockbox.

Source
Lockboxes can be obtained from the Crew Skills Slicing (missions and nodes) and Treasure Hunting, as mission rewards, or purchased from commendation vendors.

Credit
Credit lockboxes contain credits only.

Mission
Mission lockboxes contain armor or weapons.

PvP
PvP lockboxes contain consumables and armor or weapons.

Storage
Storage lockboxes contain armor or weapons.