Heavy Small Credit Box

Heavy Small Credit Box is a standard class 3 credit lockbox. Upon use, these boxes award credit 427-782.

Source
Heavy Small Credit Boxes can be obtained through the Crew Skill Slicing. They can be harvested from Biometric Footlockers on Alderaan, Balmorra (Republic), and Taris (Empire), which requires level 165 Slicing, or from level 25-32 Slicing missions.