The Whirl-Pak® Stand-Up® Thio-Bag® have a special gusset on the bottom of the bag flattens out when water is put in the bag, allowing it to stand up completely by itself. Sterile and unbreakable. Each bag contains 25 mg of active sodium thiosulfate to neutralize chlorine in the sample. With fill line and blank writing area.rBags should not be used at temperatures above 82 °C.