This is a Python package for performing calculations of crystal field (CF) properties of rare earth ions using the Stevens Operator formalism [K. W. H. Stevens, Proc. Phys. Soc. A 65, 209 (1952)]. Once the CF parameters have been initialized, the CF Hamiltonian can be diagonalized to determine the energies and wavefunctions of all the CF levels. These can be used to determine the magnetic susceptibility and neutron scattering spectra as a function of temperature.