Double Deep Racking is stores two pallets deep, or four pallets deep in a double entry rack. This system reduces the aisle to rack ratio but also reduces pallet selectivity, increasing storage density. Only 50% of pallet can be access immediately, on a FILO (First In Last Out) basis and makes good use of all available locations. This system is best used when each SKU has several pallets. The system requires the use of a special reach truck with either dual pantograph or slide fork attachments.