06-08-12 Doodle 30 (What the heck is it...)

Sorry, I can't think of a suitable title for this one. The object weighs about 2 kilos, is well constructed and it bounces when dropped. It doesn't smell of anything. It could be part of an air conditioning system or some sort of engine. When I look into one of the green vents I can see out of the opposite one. It just fits into a 20x20x20 cm box. It has no makers marks on it. I have tried to take it to pieces but it is made from very tough type of plastic and won't budge.
Any bright ideas most welcome