In pull logistics, goods are pulled by customer demand into the supply chain. For example, a bookshop may have a stack of textbooks with a signal card placed halfway down the stack. When the last book above the signal card is purchased, the bookshop knows that it is time to reorder that title. The trigger for reordering is the level of demand for the book. There will be a decoupling point in most supply chains when the ability to ‘pull’ material through the supply chain meets the requirement to ‘push’ stock into the supply chain. In the case of the textbook, it will be printed in small batches and ‘pushed’ into the supply chain. See also Logistics, Push.