Protein Molecular Weight Standards can meet different experimental requirements. Unstained Protein Markers consist of a variety of unstained proteins which allows monitoring electrophoresis and accurately estimating protein molecular weight; Stained Protein Markers with different colors are used to quickly estimate the direction and efficacy of protein transfer to membrane. Western Protein Markers with a wide molecular weight range, are compatible to a variety of secondary antibodies They can be directly exposed to x-ray film and used to accurately estimate molecular weight.