In the Kanban system, workers of a process listed the number of components required on a card called the Kanban. A worker would take the card to the preceding process and withdraw the amount required from it. The system was made up of a fixed number of containers, each holding a certain fixed quantity of parts. Each container had a set of Kanbans attached to it. Each set comprised two types of Kanbans the "Withdrawal Kanban and the Production Kanban. A withdrawal Kanban detailed the kind and quantity of product that the subsequent process should withdraw from the preceding process. The Production-ordering kanban specified the kind and quantity of the product that the preceding process must produce. The total number of containers and the number of parts each container would hold was calculated using a formula to arrive at the maximum amount of inventory that could be present in the system to hold the process together.