Yens Poly Mailers 10 x 13 M4 Envelopes Shipping Bags Self-Seal, Tear-Proof, Water-Resistant & Postage-Saving Lightweight Plastic 1000M4, 1000 Piece High quality self sealing mailers Water, tear and puncture resistant The dark grey inner layer provides confidentiality Pressure sensitive adhesive provides a high strength durable closure, water and dirt resistant Size: 10 x 13 1000 piece