As a special type of selective pallet racks there are so called "Very Narrow Aisle Pallet Racks" which have aisle, wide enough for pass handling unit, rack elevator or forklift truck with pallet, using very small operational gaps. Maneuvering of pallet unit in aisle between the racks is taking place without rotating handling unit toward to the racks. Handling unit is usually guided from the side guides in case of forklift truck or by rails in case of translator. Aisles are usually 200-600mm wider than pallet unit.