Conversion of a portable Air Conditioner from single to dual hose design

Most of the portable AC systems sold in local stores are single-hose models with two disadvantages compared to the dual-hose ones: limited cooling efficiency and creation of a a slight negative pressure in the room where they are installed.
The project is to build a box attached to the air intake grid of the AC unit and allowing the connection of a 2nd hose .
Due to its size, the box was divided in 4 identical parts. All the parts (box+hose connector) are made of abs and glued (abs juice) toge