Hook: Floor Small (Green Square)The Emergency Response Droid decoration fits into a small green square floor hook.
Hook: Floor Medium Narrow (Blue Rectangle)The Emergency Response Droid decoration fits into a narrow blue medium rectangle floor hook.
Hook: Floor Medium (Blue Square)The Emergency Response Droid decoration fits into a blue medium square floor hook.
How to Get an Emergency Response Droid Decoration
Cartel Pack Decorations
The Emergency Response Droid decoration can be dropped from Underworld Alliance Packs, which were released on the Cartel Market and bought with Cartel Coins. Cartel Packs, including the Underworld Alliance Pack, include a random selection of items from the Underworld Alliance collection of items. You aren't guaranteed to get an Emergency Response Droid decoration from a Underworld Alliance Pack, but it is one of the few ways to get an Emergency Response Droid deco apart from buying it on the GTN from another player.
If you're looking to get a Emergency Response Droid, 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.