Adjustable pallet racking is probably the most widely used type of pallet racking, and offers free access to every pallet held. It can be built to match the lift height of any fork-lift truck. Counterbalanced fork-lift trucks may be used but, owing to the wide aisles required for turning, it is more normal to use reach trucks. It consists of upright end frames and pairs of horizontal beams on which the pallets are located, and beam heights are adjustable to suit the height of the pallet loads being stored.

In theory, to optimize the use of vertical space, beam heights can be altered if pallet load heights change. In practice, this does not often occur because of the cost and disruption to the operation. Typically, two pallets are stored per bay (ie between rack uprights). The conventional way of laying out APR is to have one row single deep against the wall at each end of the installation, with back-to-back rows in between. This gives every truck aisle access to two rows of racking, and minimizes the number of aisles required. APR is a flexible, versatile storage system, which gives excellent stock access.

It is simple in concept and easily laid out, and damaged parts can be readily replaced. It can be suitable for fast-moving and slow-moving inventory. Typical utilizations for pallet positions in random-location APR can lie in the range 90 to 95 per cent, depending partly on the effectiveness of the warehouse management system handling the location information.