Advances in fork lift trucks that can operate in aisles less than five feet wide have made possible the utilization of very narrow aisle (VNA) storage racks. They provide a significant reduction in floor space devoted to aisles and often are used at heights of 40 to 50 feet. Pallets in VNA systems are 100% selective and can be accessed with turret or side loader lift trucks or be designed with top and bottom monorails.