A pull system initiates production as a reaction to present demand, while a push system initiates production in anticipation of future demand. In a pull system, production is triggered by actual demands for finished products, while in a push system, production is initiated independently of demands. Another example of a push-pull system would be when a manufacturer would stock up on raw materials (push system) but use them in production only when an order comes in (pull system). The same goes for the above-mentioned case where the company offers customization options.