An anti-magnetic damper screen was a shield technology designed to afford a level of protection against electromagnetism and magnetic fields, in use aboard Federation starships and shuttlecraft in the 23rd century.
History and specifications
In the 2270s decade, Admiral James T. Kirk ordered Scotty to fit anti-magnetic damper screens on a class F shuttlecraft. He used the shuttle in order to rescue Spock and Leonard McCoy, who had crashed on the planet Barak-7 in a Federation shuttlecraft that had not been outfitted with such a screen to weather the world's considerable magnetic fields and magnetic dust. (TOS comic: "Domain of the Dragon God!")