What kind of structure does the jumping castle have a built-in fan?

If your space is limited,then i suggest you use this special structure, build in fan can save more space for you, at least you can save 1m.

Especial you put jumping castle in shopping mall,you need leave enough space for fire protection and escape, so you use this structure very good for you.

Build in fan, no air tube outside, so when escape, player won't be tripped, and save more space.

So you must be very curious about this structure, please see the picture below.