What are the differences between Object Module and Manager Module?

I see an Object Module and Manager Module in the properties of created Document. What are the differences - Object Module vs. Manager Module?

The unit of object is a space of object with which you work now.
The manager unit are procedures and functions concerning all objects of this type (list of documents's links).

"Within object modules you can declare variables, procedures and functions that extend the object context and are available for working with the object externally using the 1C:Enterprise script. These modules contain procedures for processing various events, for example, Enter Based On. They also have various procedures to perform actions with an object that are initiated from outside the object (for example, printing).
Manager module allows you to extend the system-provided manager functionality by creating procedures and functions using the 1C:Enterprise script. In fact, this enables you to define methods for a configuration object (e.g., a catalog) that refer to the configuration object in general rather than to a specific database object instance. The manager module cannot have variables or a module body."
1C:Enterprise Developer guide

Thx, Evgeny