1906-1908 Imperforate Issues #314-320

Return of the Imperforates
In 1906, imperforate sheets of 400 first appeared to accommodate private manufacturers of stamp vending and mass-mail affixing machines who would cut the sheets into strips and paste them together end to end into rolls. Two years later, the Post Office began producing rolls of "coil" issues that could be quickly affixed to envelopes.

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