Phenomenological high precision neutron-proton delta-shell potential

We provide a successful fit for proton-neutron scattering below pion production threshold up to LAB energies of 350 MeV. We use seven high-quality fits based on potentials with different forms as a measure of the systematic uncertainty. We represent the interaction as a sum of delta shells in configuration space below the 3 fm and a charge-dependent one-pion exchange potential above 3 fm together with magnetic effects. Special attention is payed to estimate the errors of the phenomenological interaction.