The New Life/mana Steal

I recently got a Amulet which provides both Life steal and Mana steal, but Im not getting any HP or Mana back because of this HP or Mana steal.

The amulet has: (only looking at life/mana steal)

+1/2s Mana Steal
+10/2s Life Steal

What are those 2 stats supposed to give me? (Since they dont (seem) to give life and/or mana steal like it would in the old wynncraft)

EDIT: is there a chance that I only get the life or mana steal if I do damage through the element which the amulet is displaying? (Im talking about the Abyssal Amulet, reward from a lv72 quest)

 

Could someone please look at this? :)