10" x 13" Poly Mailers Poly Mailers Shipping Envelopes Self Sealing Plastic Mailing Bags Specifications: Adhesive: Synthetic rubber Hotmelt, minimum /- 1/4 . Lip Size: 1.5 /- . Liner: Clear with antistatic Opacity: Business card inside the mailer should not be visible under UV light. White/Grey Exterior, Black Interior (Interior color of mailer is subject to change). 2-millimeter thickness ( /- 5%) Approved by UPS, FedEx, and USPS. Puncture resistant and tamper/water proof. Provides excellent protection during shipments. Used to ship lighter weight items. High adhesive seal strip packages are tightly secured after 3-5 minutes sealed. Inks, Stamps, Labels adhere easily. Water and Tamper Resistant.