Hook: Floor Medium Narrow (Blue Rectangle)The Underworld Supply Locker decoration fits into a narrow blue medium rectangle floor hook.
Hook: Floor Medium (Blue Square)The Underworld Supply Locker decoration fits into a blue medium square floor hook.
How to Get an Underworld Supply Locker Decoration
Cartel Market Decorations
The Underworld Supply Locker deco is part of the Underworld Essentials Bundle, a set of decorations that you can buy directly from the Cartel Market with Cartel Coins. All decorations from the cartel market, including the Underworld Supply Locker deco, can usually be found on the Galactic Trade Network (GTN) and bought from other players with credits.
If you're looking to get an Underworld Supply Locker, the easiest way to get it is to head to the Galactic Trade Network (GTN) in SWTOR and buy it with credits from another player. You can also buy the full Underworld Essentials Bundle from the cartel market or GTN, which includes this deco and a few others that match.