4 x Heavy Duty Barrier Bags. Provides excellent puncture resistance while protecting electronics from moisture and static damage. Great protection for electronics with sharp edges. Thick, 7 mil bags will not rip when vacuum packed. Heavy Duty. Provides excellent puncture resistance while protecting electronics from moisture and static damage. Multi-layer protection guards against charges. Bags are heat sealable and suitable for vacuum packaging. WARNING: This product is intended for commercial use only. This product is not on the Qualified Product Listing under the Defense Standardization Program.