Nylon Arson Evidence Collection Bags are made from durable nylon film which reduces the potential escape of harmful propellant fumes. The clear barrier bag allows the contents to be seen without opening the evidence packaging. Use the bag alone or place inside a metal can to help safeguard evidence from contamination during storage. A Heat Sealer should be used to seal these bags. Use a double seal to provide extra security. Oversize shipping charges may apply.