Planetary Gear System
The large red gear is unmounted, held in place by it’s neighbor gears, which are referred to as Planetary Gears. The red gear is actually a Disc Gear in a Planetary Gear System, but here it has planets on the inside and outside, holding it in place. If the two white pieces in front of the red gear are popped off, the gear can be freely removed.
The little box in the corner holds a bottle of 3in1 oil which helps the gears spin much nicer.