Level 1 sheilds are the stronger level of sheilds although unable to block solid objects just the electro-magnetic energy stored inside.
They are not different to the Level 2 Sheild Generators its just a different range of Power flow and sheilding Frequancy.
Level 1 sheilds were first encountered by Humans in 2015 in The First Destruction, where scientists realised that the missiles can make it through but the electrics were knocked out by a EM sheild, they then thought of the PDS and with that destroyed the fighters.
Most Ships still use Level 1 sheilds as they block energy and electro-magnetic missiles but as soon as either Ship launches Fighters and Missiles the ship switches to level 2 shields.
Russian Rebelious Goverment.