Hook: Floor Medium Narrow (Blue Rectangle)The Austere City Bench decoration fits into a narrow blue medium rectangle floor hook.
Hook: Floor Medium (Blue Square)The Austere City Bench decoration fits into a blue medium square floor hook.
How to Get an Austere City Bench Decoration
Cartel Pack Decorations
The Austere City Bench decoration can be dropped from Architect's Stronghold Packs, which were released on the Cartel Market and bought with Cartel Coins. Cartel Packs, including the Architect's Stronghold Pack, include a random selection of items from the Architect's Stronghold collection of items. You aren't guaranteed to get an Austere City Bench decoration from a Architect's Stronghold Pack, but it is one of the few ways to get an Austere City Bench deco apart from buying it on the GTN from another player.
If you're looking to get a Austere City Bench, 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. If it's very rare and not available on the Cartel Market, you could try buying from the GTN and hope you get it.