the title is a little bit over the top because there is only one trailer in the pack, but there is more :)
This is the K.SHG AVMH / 45 - 15/27. An extendable gooseneck chassis for transporting 20 'to 45' containers
Excerpt from the website of Kässbohrer:
The Kässbohrer Gooseneck container chassis are designed for maximum flexibility in all operations.
Due to the hexagonal gooseneck construction and a larger wall thickness, the load is distributed more evenly at the front, especially during loading, which contributes to the resistance and longer life of the trailer.
The chassis is extendable to transport containers from 20 'to 45'. For this, the locking positions for the best adjustment and load distribution can be changed.
1x20 'ISO container
1x40 'ISO container
Credits: Alfredix, GIANTS