Shields in general will block all incoming damage from the direction the user is facing.
Damage is absorbed 1:1 from any shot that hits the shield, meaning if a shield absorbs a 40 damage dealing plasma round it will lose 40 points of health.
The shield has a 100% chance to absorb a hit that hits the user directly in the front, however shots from the side have a chance of missing the shield and hitting the user. Once a shields health has been depleted any remaining damage will be applied to the user and the shield will be destroyed.
Combat Shield Edit
The combat shield is available at the start of the game, under the Equipment Tab. It has 80 HP, and it is too big for a soldier's inventory. The Combat Shield is extremely useful as a tool for scouts and breaching units.
Assault Shield Edit
The Assault shield functions exactly the same as a Combat shield except that it must first be researched and has 160 HP, double that of the combat shield.