Energy shield
The Energy shield generates a basic protective shield around your character, absorbing a small amount of Damage.
The shield is effectively an extension of hp and has to be brought to 0 for the character to suffer any actual hp damage. Like actual hp, it benefits from your armor.
http://www.factorioforums.com/forum/viewtopic.php?f=18&t=1943
| Recipe: |   |
| Total raw: | |
| Shield: | 50 |
| Energy per unit: | 20 J |
| Recharge speed: | 6 |
| Size: | 2x2 |
