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