Nostalrius Begins - Quality wow vanilla realm (1.12)

Is that trinket in the game and useable by lower level players? I keep seeing Alliance popping a priest looking absorb shield when im attacking them, but there is no priest nearby and they are not getting the debuff either. So i guess what item are they using thats giving them a shield like that? And I know its not the warlock sacrifice shield, that looks different.

yes

that and agm

Physical dmg only

You need to be Friendly to buy it, it's a shield that blocks a bit of physical damage on a 2min CD.