It's also called Hot Glue in English.

Was that the X-Arcade or his €15 stick he disassembled?

Many die hard Arcade game fanatics don't like the X-Arcade because they make their own parts instead of using the official arcade components from Happ, but I personally like the X-Arcade controller. The HotRod which is similar to the X-Arcade does use official Happ control parts and it isn't that different. The official Happ components do have a slightly different feel with the sticks being a bit stiffer and the buttons having more of a click, but it is really just down to person preference with such things. I think the build quality of the X-Arcade is really good and will last many years.