Spectral energy distribution of the system 4U 0614+091 built starting from the radio (green triangles) and infrared points (blue squares) of Migliari et al. (2010), from the ALL WISE catalogue magnitudes (red circles) and from the r-flux obtained in this work (black x). With an orange arrow we indicated the W3-band WISE upper limit obtained from the ALLWise catalogue. Superimposed, the two linear fits of the SED. All the points are normalised to the fluxes of Migliari et al. (2010).