that's 068 129 902 elbow with cyclone function as fitted to 1.7KY late vans only, wasn't designed to go with 1.6TD but may work
the small hole on the bottom would originally have had a rubber extension on it and acts as a debris dump and moisture dump, the rubber bit may have had a mouth on it that you squeeze to open and empty, but I haven't seen one in the flesh, just going off the parts diagram
new they are over £100
