How long is my USPS prepaid shipping label for?

When you order a "Headache Free Out of State Kit" from Binary Biometrics we include a Prepaid USPS Priority return shipping envelope with postage. All prepaid shipping envelopes with postage will expire six months after they are issued from Binary. If you think your postage may no longer be valid please check with your local post office first, and if the postage is expired you will need to purchase postage.