= Gaussian units
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<Gaussian units> are an electromagnetic unit convention in which factors of the <speed of light> and $4\pi$ appear differently from <SI>. In vacuum, the electrostatic <Coulomb's law> is written $F=q_1q_2/r^2$ for two point charges, with no explicit $\epsilon_0$.
The convention changes the dimensions assigned to <electric charge>, not the predicted <force>. For example, the <Lorentz force> is written $q(\mathbf E+\mathbf v\times\mathbf B/c)$ in <Gaussian units>, whereas <SI> uses $q(\mathbf E+\mathbf v\times\mathbf B)$. One must convert the quantities and equations together: inserting <SI> field values into an unchanged Gaussian formula gives an inconsistent calculation.
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