Booster Shields are a commonshield type in Borderlands 2. They are manufactured almost exclusively by Dahl. The Booster Shield is obtained randomly from any suitable loot source.
Usage & Description
Whenever a Booster Shield is hit while active it has a set chance to drop a special item, a shield booster, which will recharge up to 25% of the shield when picked up. Booster Shields may offer resistance or immunity to elemental damage.
A shield booster dropped by one player's shield may not be picked up by any team members if their shields are full. If enemies are equipped with such shields, their booster items are not available for any other player to use.
Pot O' Gold - UniqueBandit-made Booster Shield that has a chance to drop money when hit.
Big Boom Blaster - SeraphTorgue Booster Shield that will restore one grenade and one rocket as well as the shield bar.
After being dropped for some time, boosters will start gradually shrink its size. Booster size does not affect its effect when picked up, but when it become small enough it will disappear. Boosters disappear faster than normal loots.
Very rarely, human enemies can be equipped with a Booster Shield, and drops booster when their shield is damaged, this is generally an advantage to players, as most enemies will not try to pick up dropped Shield Boosters, and the shield strength of most enemies are rather weak.