Reinforced Small Credit Case

Reinforced Small Credit Case is a standard class 3 credit lockbox. Upon use, these boxes award credit 371-645.

Source
Reinforced Small Credit Cases can be obtained through the Crew Skill Slicing. They can be harvested from Security Mainframes on Tatooine and Alderaan, which requires level 125 Slicing, or from level 25-32 Slicing missions.