Can you explain the difference? I understand that the jersey protects your skin from the direct solar rays. But otherwise it seems like what you want is to get sweat from the skin to the outside of the jersey where air flow will evaporate it. It seems like making the sweat go through the base layer, transfer to and through the jersey, and then evaporate is just going to slow down the evaporation, compared to just wearing a jersey that wicks moisture as well as the base layer material.