This model snaps into the hole behind the power supply in the NR200 case through which the power supply intakes air. Normally there is a gap between the PSU and the ventilated side panel of the case, which allows the PSU to intake warm air from inside the case. With this duct that gap is mostly blocked off and the PSU is forced to intake fresh air through the mesh side panel.
The side should be such that it snaps and stays, if it doesn't you can either remove some material or add a layer of tape to make a good fit.
The author hasn't provided the model origin yet.