12″x15.5″ IS THE ACTUAL USABLE SIZE3MIL for Super Extra Strength!White exterior with Grey interior for privacy!Great for shipping a very wide range of non-fragile items like Clothing, Shoe box, Gifts, etc.Premium Quality: These envelopes have a good stretch, lightweight, puncture & water-resistant!Tear Resistant: The adhesive on the fold-over flap is like permanent glue and so tamper-evident!Simply pack, peel and seal!Lower shipping cost for your business!Approved by USPS, FedEx, UPS, DHL, etc.100% recyclable!***Need large quantity or have questions? Please message us! Thanks