Push Back Pallet Racking (PBR) – There is a slight incline provided between the front face and back face of the rack such that the pallets at the back automatically slide to the front when the pallets at the front are removed from position. Storage is achieved by pushing the front face pallet with the pallet on the forklift such that it slides back and then the new pallet is placed in the system. POA. The system uses the FILO principle for access of any pallet in the system.