the offer is valid for one complete Case with 16 Blindboxes.

 The figures are 3inch (ca. 8cm) tall. The figures are in blindboxes. Per Box one figure. You cant determine wich one you get. 
 

Original welded case
There is no guarantee that you get all characters with one case. 
With the purchase of one case there is no guarantee that you will receive all the characters. The figures are available in different rates. It could be that there is a  Rate of 1 or 2 of 16 blindboxes. That mean that the figur is one ore two boxes of 16 boxes. But other rates 1/20 ore 1/80 or ?/?? are possible.
Rare figures are very popular by the collectors and usually rise in value. By this different rates it is unlikely that you get all the characters with with one case

What is a blindbox:  
A Blind Box is a type of packaging that keeps its contents hidden. They are identical in every way and nobody--including us--knows which toy is inside. The package are glued and everyone open a box you can see it. The figures inside are a nontransparent foil. The foil are frozen. 
You can´t determine wich one you get. It´s a surprise.