Durabright wants to establish kanbans to feed a newly installed work cell for its line of LED traffic signal lamps. The daily production (demand) rate for this new family of products is 40 units. The supplier lead time for the bulb housing, used by all products in this product family, is 4 days. They want to keep 1.25 days of safety stock of this housing on hand (the safety stock factor). The kanban size for the bulb housing components is 20 units. How many kanbans do they require? (Display your answer to the most appropriate whole number.)