Squad shields were devices used to generate large personal energy shields.
They were mobile deflector shield generators that could be physically placed on the ground to cover anything within its range from blaster fire, typically large enough to encompass multiple people fully standing. It wasn't able to defend against physical projectiles however, such as rounds fired from scatter guns and cycler rifles.
The protection was seemingly only meant to be temporary, as the energy field would break if repeatedly shot. It was also able to be remotely deactivated by the person who placed it. The color of the field produced could vary between bluish-purple and green.
Squad shields were utilized by some members of various armed forces in battle. Officers often carried them when they found themselves in combat situations. They were used by the Galactic Republic and the Confederacy of Independent Systems during the Clone Wars, the Alliance to Restore the Republic and the Galactic Empire during the Galactic Civil War, and the Resistance and First Order during the First Order-Resistance War. Leia Organa was equipped with one stronger than the average model.