The internal structure of the fiber distribution box is made in a way that helps it perform its functions. As you already know, the main work of the distribution box is to protect and also split the fiber.
So, in a nutshell, the internal structure can be divided into four different parts. Each part has a specific function to perform.

Here are the four parts:
Fiber Splitter Disks
Some fiber distribution box models do not have these disks, but good ones have it since it serves an important purpose. The disks serve as a fixture whose role is to make it easy for you to install pigtails and splitters.
While you might see varying shapes of these parts in different fiber distribution boxes, their function remains the same. The difference is a result of different brands trying to improve their models.
Different shapes determine how you will do your fiber fusion as some are more convenient in some applications. You are, therefore, free to choose that which you think will help you serve the purpose conveniently.

Cable Inlet
When it comes to making fiber connections or terminals, there will always be some cables entering from the outside. Cable inlets are the ones you will use for access purposes for external fiber optical cables.
The cables you will insert help in fastening the access port. It is, therefore, not easy to loosen cables in the fiber distribution box.
You should also note that the cable inlet is usually placed under the box. The positioning is intentional as it helps avoid water entry into the box, especially for outdoor applications. The inlets are also waterproof.
Outlet
Different fiber distribution boxes have a different number of outlets. A great majority of them normally have 8 outlets, hence they are called 8-core boxes. That is to say that, the number of outlets determines the model.
When it comes to the feature, these outlets are usually smaller than the inlets. The reason is that the cable that enters the distribution box is bigger than those leaving.
Splice Tray
Usually, the fiber optical cable from outside has to have a connection to the splitter. To make the connection, you will have to weld the cable to the splitter of the distribution box. The splice stray makes it easy to do the welding.
