The specificities are the particular details or characteristics of something.
Knowing the specificities of something can be very helpful because it gives you a clear understanding of it.
Examples:
The specificities of the plan are important to understand.
She knows all the specificities of the project.
The specificities of each animal are different.
The specificities of the game make it fun to play.
The specificities of the rules are very strict.
He understands the specificities of the problem very well.