1.Is a submerseable pump that is used for water circulation. A powerhead will work. 2. Is a plastic output tube for the pump, this is where the water exits the pump. You should have cut a small slit in the 2 mm screen so that the tube can pass through it. You may need to cut some of the eggcrate so that the tube can fit through it, depending on the size of your tube. Below is the same picture, just viewed from the top with the eggcrate and accompanying fiberglass screen removed.