c++11 - Strange declaration with using in C++

On a piece of code in a previous question in stackoverflow I saw this, strange to me, declaration with using:

template  
class A

{
public:
  ...
  using const_buffer_t = const char(&)[SIZE];
  ...
};

Could someone please address the following questions:

1. What type it represents?


2. Where do we need such kind of declarations?

Answer

That's a type alias, a new syntax available since c++11.

What you're actually doing is typedefing the type of an array

const_buffer_t 

will be an array of const char with length = SIZE