Hook: Wall Medium (Blue Square)The Engineering Access Panel decoration fits into a blue medium square wall hook.
Hook: Wall Large (Purple Rectangle)The Engineering Access Panel decoration fits into a large purple rectangle wall hook.
How to Get an Engineering Access Panel Decoration
Cartel Market Decorations
The Engineering Access Panel deco is part of the Republic 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 Engineering Access Panel 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 Engineering Access Panel, 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 Republic Essentials Bundle from the cartel market or GTN, which includes this deco and a few others that match.
Contributors: Thank you Solomon for allowing me to take screenshots of this decoration!