+1 to maximum Energy Shield per 6 Evasion Rating on Body Armour
5% increased Attack and Cast Speed per Ghost Shroud
Cannot be Stunned while you have Ghost Shrouds 
Escape Artist is a notable Ascendancy passive skill for the Trickster grants evasion rating per energy shield on your equipped helmet and energy shield per evasion rating on your equipped body armour. It also grants increased attack speed and cast speed per charge of Ghost Shroud from Ghost Dance and grants stun immunity while you have Ghost Shroud.
Bonus evasion/energy shield from helmet/body armour is not part of the item, so it is unaffected by quality and does not factor into mods that scale off the item's base values, such as X% increased Energy Shield from Body Armour.