Gilded Medium Credit Box

Gilded Medium Credit Box is a premium class 4 credit lockbox. Upon use, these boxes award credit 806-1636.

Source
Gilded Medium Credit Boxes can be obtained as a mission reward or through the Crew Skill Slicing.

Slicing
They can be harvested from Holographic Microcomputers on Alderaan, Balmorra (Republic), and Taris (Empire), which requires level 205 Slicing, or from level 33-40 Slicing missions.