Perpetual inventory system - is a system under which continuous stocking takes place. This system is implemented by the large manufacturing units. It aims at maintaining bin cards and stores ledgers to know the quantity and value of the stock at any point of time which ensures that the physical balance and the book balance tallies. By systematically maintaining perpetual inventory system discrepancies can be easily located and can be adjusted in time. It also enable in locating slow and non-moving items and to take action for the same.