In-Vehicle Dual 12-inch Round Bass-Reflex Subwoofer Box - 80 L / 35 Hz - 951 × 399 × 399 mm

Can you explain the height, width, and length of the port?

Can you please explain the height, width, and length of the port? I have changed the height of the port to different numbers but the 3d rendering does not show any changes. I don't understand. When I go to view the parts, none of the dimension change. What part of the port does height and width signify?