system
Given the following post, respond as if you're commenting on Reddit:
human
[Culture] What exactly are Displacer units, and how do they compare to forms of FTL travel found in other popular SciFi ‘verses?
gpt
Displacers encapsulate matter in a containment field and then shunt it through hyperspace to another location in realspace. The energy requirements rise dramatically with the amount of mass and the distance displaced. Culture Displacers were precise enough to accurately deliver chemicals into a biological body for medical purposes, but the largest shipboard and orbital based ones were powerful enough to move a small starships across a system. Some Culture ships could even execute "snap" displacements where they're moving at high speed relative to the target, sometimes with less than a second in range of the target. 

Shields that extend into hyperspace (standard in the Cultures' galaxy) can block displacement since they block hyperspace.  

The biggest drawbacks of displacement as a form of FTL travel are that it relies on a separate unit (external to the mass being displaced) and it quickly scales to be massively more difficult than  simply putting a hyperspace field engine on the object and having it move itself directly.