Champion Thread’s Champcot Plus is high grade long staple cotton that has been gassed and mercerized. Champcot Plus is designed for sewing articles that are to be overdyed. Because Champcot Plus has been gassed and mercerized and utilizes high grade long staple cotton, it has a greater affinity for dye stuffs than non mercerized cotton. Mercerization also makes Champcot Plus stronger and more forgiving in overdye operations.