This category of measurement units is defined by the "electric current" type, which is an SI base quantity.
The SI base unit for electric current is the ampere.
In physics, the ampere (symbol: A, often informally abbreviated to amp) is the SI base unit used to measure electrical currents. The present definition, adopted by the 9th CGPM in 1948 is: "one ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one metre apart in vacuum, would produce between these conductors a force equal to 2 × 10-7 newton per metre of length".