Values of physical constants CGS < MKS < SI. Read wikipedia on CGS and SI system for more details.
International System of Units (French: Système international d'unités, SI), historically also called the MKSA system of units for metre–kilogram–second–ampere.
The SI system of units extends the MKS system and has 7 base units, by expressing any measurement of physical quantities using fundamental units of Length, Mass, Time, Electric Current, Thermodynamic Temperature, Amount of substance and Luminous Intensity, which are Metre, Kilogram, Second, Ampere, Kelvin, Mole and Candela respectively.
http://www.npl.co.uk/upload/pdf/units-of-measurement-poster.pdf
module SI : sig ... endmodule Prefix : sig ... endmodule MKS : sig ... endmodule CGS : sig ... endmodule CGSM : sig ... end