This application allows retrieval of aerosol properties from AOD measurements with a variable spectral range based on the published work of Torres et al., 2017. The application is limited of having at least one AOD-measurement between 500-800nm, one under 500nm and another one above 800nm.  The refractive index, real and imaginary part, should be given for the selected wavelengths and it can be spectrally dependent or independent. Once the inversion is running, the users will get a representation of the retrieved size distribution as well as a table with the main outputs of the retrieval:  the six parameters that describe the bimodal lognormal size distribution (volume median radius (rVi), standard deviation (σVi) and volume concentration (CVi) for fine and coarse mode) and a set of secondary aerosol properties derived from it. In particular, the effective radius, the total concentration and the theoretical value of the fine-mode τa at 500 nm. The code is slowed down in order to see the evolution of each iteration.