This Whirl-Pak® Coli-test bag for color-changing reagents measures 3 x 7-1/4in (7.5 x 18.5cm) with a thickness of 2.5mil (0.064mm). If water samples are being tested with color-changing reagents, this bag can be used in place of the expensive bottle currently used. The bag is made of a special barrier film suitable for use with enzyme-based methods that result in a chromogen and/or a fluorogen release when total coliform and E. coli are present. The special film prevents color change from permeating through the bag, contaminating another sample and creating a false positive, and making contact with a person’s skin if they are not wearing gloves. It is sterile, contains 10mg of active sodium thiosulfate to neutralize chlorine, has 4oz and 100mL fill lines, and is completely self-standing (no rack or holder is needed to keep the bag upright). If the sample is not chlorinated, this bag can still be used. The sodium thiosulfate will not affect the sample, as it is nontoxic and nonnutritive, and only neutralizes chlorine if present. A free color comparator is included in every box. The Coli-test bag has been accepted by the EPA and is listed in the EPA Manual for the Certification of Laboratories Analyzing Drinking Water Section 188.8.131.52, 5th edition, January 2005. The Coli-test bag will save money three ways: less expensive than the bottle, lower freight charges, and reduced disposal costs. A box containing 100 bags measures 9 x 7 x 2in (23 x 18 x 5cm) and weighs 1Lb (0.40kg), compared to a box of bottles which has considerably more volume and weight. Sterile. Material: Polyethylene. Dimensions (W x L): 3 x 7-1/4in (7.5 x 18.5cm). Thickness: 2.5mil (0.064mm). Fill Lines: 4oz And 100mL. Active Sodium Thiosulfate: 10mg. Feature: Self-Standing. Capacity: 100mL. Nasco® #: B01417WA.