5np, 10np, 15np, 20np, 25np and 50np with 6 digit serial numbers on the back are from the coils of 810 stamps, each prepared horizontally from sheets of automatic vending machines where public can purchase frequently used denominations by inserting coins in appropriate slots. In Parliament Street Post Office (New Delhi) it was experimented. However due to technical difficulties and poor response from public further machines were not purchased and the stamps were sold over the counter manually.