The solar flux unit (sfu) is a convenient measure of spectral flux density often used in solar radio observations, such as the F10.7 solar activity index:[1]
See jansky for further information about related units; one Jy = 104 = 10−26 W⋅m−2⋅Hz−1 = 10−23 erg⋅s−1⋅cm−2⋅Hz−1.