Stops running water instantly. Nonshrinking; expands as it sets and won't pull away from edges of patch. Will set up under water. Sets fasts: 3-5 minutes. Exceptional structural strength. Dry powder form, just add water. Easy-to- mix and put in place; requires no special equipment. Nontoxic when set. Nonmetallic; will not rust out or deteriorate. 1 lb. of water plug will seal running water out of a crack 3/4" D. x 3/4" W. x 30" L. Metal pail.