Some people like the flexibility of being able to add and remove rings to adjust for larger and smaller loads.  This is also useful when firing tall sculptures.  The rings could be removed from the kiln, the sculpture place on the bottom of the kiln, and the rings lowered down over the sculpture.  

However because of the Easy-Lift, Easy-Load spring-loaded counter-balanced hinge (which is now standard on L&L 29" diameter kilns, and optional for others), this is not easy to do.  The lid lift mechanism is highly integrated into the structure of the kiln, and it's difficult to take it off and on for every firing.

Therefore, L&L offers the no-cost "Pull-Apart Option."  In this option, there is no hinge or lid-lift assist mechanism at all.  The lid lifts off manually, with 4 handles, and the control box is mounted on a separate stand from the kiln.  This makes it extremely easy to add and remove rings.