These mailing bags incorporate a permanent self-seal closure and are made from an opaque 60 micron in thickness / strength , Coextruded strong mailers A pack of 100 strong grey mailing postal bags, size 13x19 (330mm x 485mm), with a 40mm 'peel & seal' lip. These mailing bags are extremely high quality and are 60 micron in thickness, like all the other sizes we stock Edenpack mailing bags provide you with the best quality 100% Opaque Mailing Bags. Grey Mailing Bag 300mm X 900mm – Self-Seal Poly Mailer Strong Plastic Postal Bags SHRCMHWQRCDJ 100pcs Plastic Mailer Bag Shipping Package White Envelope Bag Postage Poly Bag Packaging Bag, For Delivery (Size : 20X30 CM-100 PC Self Seal Mailing Bags High performance 55mu bags, strong adhesive with 40mm peel & seal strips NB 12x15.5 Inch – 10 Pcs White Poly Mailers Strong Adhesive Self-Seal Shipping Envelopes, Tear & Water Resistant Packaging for E-Commerce and Small Biness Once sealed, these bags are very hard to open allowing your items to arrive safely without risk of opening or tampering. Safe and Secure- these plastic mailers have a sticky strip for easy closure.