These 9x12 inch mailer bags are useful for many non-breakable items, such as small cosmetics in durable packaging, t-shirts, blankets, pants, books, and many other items. These shipping bags are durable with a sticky strip to tightly seal the mailer.In addition to being self-sealing for easy packing, the bags are also waterproof. The plastic mailing bag is thin, durable, and flexible, which allows for it to hold objects of varying shapes and sizes, such as cylindrical and square objects. Refer to video for visual tests. Hassle free self-adhesive strip makes packaging a breeze. Get your orders out faster and without spending extra money on tape. Tamper proof seal prevents others from opening the mailer without damaging it.Our poly envelopes will not show your contents on the inside. Ship se