Material specifications for the SendPro C, SendPro+, SendPro C Auto

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Products affected: SendPro® C, SendPro®+, SendPro® C Auto (2H00, 8H00, 9H00)

Review the material specifications including the minimum and maximum envelope sizes, envelope stack height, and tape size details.

Envelope Size

  • Minimum: 3.5 x 4.75 in
  • Maximum: 13 x 15 in

Envelope Flap Depth

  • 3 in

Envelope Thickness

  • Minimum: 0.02 in
  • Maximum: 5/16 in

Stack Height for Mail

  • 3 in – this is the height of the inner edge of the side guide

Envelope Weight

  • Minimum: 0.035 oz
  • Maximum: 16 oz

Tape Size

  • Minimum: 1.75 x 4 in
  • Maximum: 1.76 x 8 in


For a proper seal, the envelope’s minimum flap angle must meet the following criteria:

  • For envelopes with a flap length from 1-2.36 in, the minimum flap angle is 18 degrees.
  • For envelopes with a flap length greater than 2.36 in to the maximum flap length for the particular model, the minimum flap angle is 21 degrees.


UPDATED: July 23, 2021