GFS Chemicals manufactures the Watermark® Karl Fischer product line. We have one of the largest selections of Karl Fischer reagents in the industry, and the technical expertise to meet your project's needs. From volumetric and coulometric Karl Fischer reagents to certified water standards, we have the products you need in stock and ready to ship. GFS Chemicals also offers both pyridine and pyridine-free solutions. Our Watermark Karl Fischer coulometric reagents have a water capacity over 1000 mg/mL.