$\textit{Electron Radius}$, also known as the Lorentz radius or the Thomson scattering length, is based on a classical (i.e., non-quantum) relativistic model of the electron.
Applicable units are those of quantitykind:Length
http://en.wikipedia.org/wiki/Classical_electron_radius
"Electron Radius", also known as the Lorentz radius or the Thomson scattering length, is based on a classical (i.e., non-quantum) relativistic model of the electron.
$r_e = \frac{e^2}{4\pi m_e c_0^2}$, where $e$ is the elementary charge, $\varepsilon_0$ is the electric constant, item $m_e$ is the rest mass of electrons, and $c_0$ is the speed of light in vacuum.
http://www.iso.org/iso/catalogue_detail?csnumber=31895