The Poly Mailer Bubble Mailers are 8"x5" padded envelopes made of 4-layer composite polyethylene bubble film, featuring a 4cm sealing flap for secure closure. These white mailers are waterproof, moisture-resistant, and tear-resistant, providing protection for items during shipping. With 100 pieces in a pack, these self-sealing mailers are suitable for use with USPS, UPS, DHL, and FedEx, making them ideal for businesses in need of reliable packaging solutions. Made in China, these mailers offer a convenient and durable option for shipping various items securely.