The IRIS11 Prestained Protein Ladder is a combination of 11 pre-stained proteins with molecular weights from 3 to 260 kDa. The 11 recombinant proteins are covalently coupled with blue chromophore, while 2 red bands at 70 kDa and 260 kDa, a green band at 15 kDa and a newly designed peacock green band at 60 kDa serve as reference bands. The IRIS11 Prestained Protein Ladder keeps track of the size and separation of proteins during SDS-polyacrylamide gel electrophoresis, approximating the target protein size and validating the Western transfer efficiency on PVDF, nylon, or nitrocellulose membranes.