The Absolute Best Biohazard Bag available!! These American-Made tri-wall specimen bags are 2-mil thick with document pouch and our patented “Double Grip Zip” closure. Our special closure system makes these bags so much easier to open, close, and reopen. Ideal for large volume, specimen processing applications. These are hands down the best Bags on the market. Pack of 500-bags Also available in other sizes and quantities.