These Opaque Mailing bags incorporate a permanent self-seal closure and are made from an opaque 60 micron film. Our posting bags have a self-adhesive strong closure. These air sealed postage bags are water and dirt resistant and made to secure the inside and outside. Safe and Secure Package Bags:- These plastic mailers have a sticky strip for easy closure. Once sealed, these bags are very hard to open allowing your items to arrive safely without risk of opening or tampering. Small to Large Mailing bags. Parcel bags for posting Mailing Packaging and more Plastic envelopes for posting:- iSOUL Small to Large postage bags are very light weight and sturdy. You can use its full size or put something smaller inside and wrap the excess before sealing. These Plastic Postage Bags can be used for any Courier or sealed Airtight storage Purpose, you will get these bags in five different sizes, ideal for packing items of all types, shapes and sizes. The self-seal lip makes the parcel air tight and water resistant for personal and business use.