Explain the Zero stage channel of distribution

Zero stage distribution channels exists where there is direct sale of goods by producer to the consumer.  This direct contact with the consumer can be made through door-todoor salesmen, own retail outlets or even through direct mail. Additionally in case of perishable products and certain technical household products, door-to-door sale is an easier way of convincing consumer to make a purchase. Eureka Forbes, for instance, sells its water purifiers directly through their own sales staff.