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