Our peel-and-seal white poly mailers are made from durable 2.5 mil coextruded (COEX) low-density polyethylene (LDPE). This means the items you mail in a poly mailer will be water, puncture, tear, and tamper resistant giving your product added security, and peace of mind. Designs work for Christmas, birthday and everyday gift giving. Solid colors plus FaLaLa Christmas text. An added benefit of plastic mailing envelopes is their high-strength seams. This allows you to overstuff the bag when you are shipping soft lightweight items (like clothing) USPS first class.