The medium base is exactly half the size of full bank. It fits ONE large kennel, or  TWO Medium size. Small will NOT fit as they are not deep enough(you could use plywood or some other material to build a "floor". 

Rolling cage base is the metal frame that the cages will sit on top of so that you can roll the whole bank away and clean. it also is tall enough that you can simply vaccum or sweep and mop under it without moving it. 

 They are equipped with 4" heavy duty zinc plated casters which rotate 360° for easy maneuverability. The front wheels lock, allowing the assembled kennel to remain stationary. 

Medium Rolling base cage dimensions 46.5"(L)×26"(W)

Assembly required. Rolling Base comes in pieces in one box.  it will require freight