Marcel got a Goso pickgun and it included some items of which the use was not clear right away:
After some researching on the internet, it turned out that these are meant to pick certain magnetic locks that are manufactured in China. Outside of China, you will likely not come across these locks.
The silver coloured piece can only turn, the brass piece has a push knob at the end. After some googling, Marcel found a YouTube video explaining the lock (not the tool), made by Lockman28, to be found at https://www.youtube.com/watch?v=8ZNUgsplYk4.