The Particle Wall creates a concave force field which blocks all projectiles from one side and lets all projectiles through from the other. The force field exists for certain period of time and degrades from enemy damage. The remaining lifetime is indicated by the field's color. In Titanfall, shield has a maximum duration of 8 seconds, decreased by enemy fire.
Particle field does not block melee attacks, Electric Smoke or Cluster Missile explosions (however, the missile itself will explode upon impact).
The Reinforced Particle Wall kit, available to Tone in Titanfall 2, buffs the Particle Wall by allowing it to take more damage and last longer before dropping.
Aside from the base Titan variant, there are several other uses of Particle Shield technology; the Gun Shield, used by Legion, is a Particle Wall wrapped around the Predator Cannon.
Pilots also get their own Particle Wall variants, being the Hard CoverBoost and the A-Wall tactical ability. They both function the same as their Titan variants,with the exception of being smaller and the latter Amping the weapons fire that passes through the wall.