The artefact that has defined the kilogram since 1889 is to be retired and the kilogram will instead be defined by fixing the value of the Planck constant. In this chapter, I detail some of the elements of this reform, believing that the case study should prompt philosophers to reassess the role scientific standards play in the progress of the physical sciences. A metrological account of scientific standards should explain metrology’s more theoretical motivations and also acknowledge its empirical contribution to the physical sciences. I present three theses towards this end. I develop a more thoroughgoing and yet much weaker version of Bridgman’s operational attitude. I present a picture of the physical sciences united by metrology. Finally, I present the case for a quiet form of realism that attempts to accommodate both the more theoretical and the more pragmatic motivations of the metrologist.