Kem-Kromik 255Technical Information Sherwin Williams Kem Kromik 255 (formerly known as Steel Spec M255) is a anticorrosive protective finish for use as a single shop applied protective finish for structural steel that will not normally require further site coats. Where To Use: As a single coat shop applied protective fi nish for structural steel that will not normally require further site coats. Suitable for use as a single coat system on internal or external steel.