The Pot Lid is circular with two circular handles on it, one on each side. There is another handle in the center of the Shield. The center handle is black, but the rest of the Shield is silver.
It likely refers to how Vexen "keeps a lid on" things.
The Pot Lid's ground combo begins with a jab forward, followed by a jab to the left. After the latter, a -Combo is prompted, which upon initiation will execute another jab forward, which can then chain into the combo's normal finisher with another tap of the button. In the normal combo finisher, Vexen will position his Shield behind him, then hurl it forward, sending it a good distance away before it flies back into his hands.
The Pot Lid's aerial combo is a simple 360° spin of the Shield, which will come to rest in front of Vexen before flying back into his hands.