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