Our SuperBlue G250 stain is a colloidal Coomassie formulation with a sensitivity of ~20-40 ng protein. As a colloidal stain, the SuperBlue G250 reacts only with proteins and not the gel itself, resulting in a reduced background staining that permits rapid visualization of the gel bands. Protea's SuperBlue R250 stain is a traditional Coomassie stain, with a sensitivity of ~20-40 ng. Because Coomassie stains interact stoichiometrically with protein in gels, they are useful for quantitation by densitometry. The SuperBlue G250 stain is available as a ready-to-use formulation, while the SuperBlue R250 stain is provided as a 10X concentrate solution.