Your Constitution score is 19 while you wear this amulet. It has no effect on you if your Constitution is already 19 or higher without it.
Notes: Set: Constitution Score, Buff, Jewelry
This item would not change your AC unless you are playing a barbarian with there "Unarmored Defense" class feature. This would increase your HP of any character but it does require attunement which once equipped there will be an additional button for that. There is also a 3 attuned item limit.