A knob or pull is necessary to open a lipped cabinet door because of how securely it is matched to the cabinet frame. To create a lipped cabinet door, cabinetmakers must notch the backside of the cabinet door to the exact dimensions of the cabinet frame. This is a very precise form of cabinetry that requires accurate measurements and perfect hinge movement to prevent problems associated with the tightly fitting inset portion of the doors. This is not a typical form of cabinet door offered because of the extensive labor required to properly install it. Choosing lipped cabinet doors will typically be the result of needing a more secure closure on the cabinets.