The Square Lid is used in the 3Dponics Cube System to cover the Square Pot as well as to hold and support the Planter. It has built-in openings for the Planter, tubing and air circulation vents. It also has a small grip so you can lift the lid easily once it's closed. Know how to make this part better? Have ideas for new parts? Visit our website (https://www.3dponics.com) and join our Google+ community (https://plus.google.com/u/0/communities/111638904033818784260) to take 3Dponics to the next level!