The name refers to the long strips of stamps resembling a roll of tape. The development of coil stamps was a long and difficult process as a machine to automatically perforate and dispense coil stamps had to first be invented. The United States issued its first coil stamps in 1908 and a new area of stamp collecting was discovered. Many different types of coil perforating machines were tested until one was selected to be used on all United States coil stamps. Originally, sheets of stamps were cut into strips, or rows, of 20 stamps. Workers took these strips and pasted them together to make large coils of 500 - 1000 stamps. This was a very long and labor intense process. The use of the rotary press eliminated some of the labor required to make the rolls of stamps and soon workers were making rolls of 6000 stamps. Coil stamps soon became very popular with large businesses. The companies used machines to apply coil stamps to their advertising mail and this was much more efficient than having workers hand apply stamps to the outgoing mail. Coil stamps are easy to identify by their having straight edges on the top and bottom (horizontal coil) or straight edges on the right and left margins (vertical coil). There are a few "tricky" stamps that resemble coils but are actually larger stamps that were issued in a booklet format. For additional information on these "tricky" stamps please see the page on booklet stamps.