A magical armguard that when put on creates a 2nd armguard that is not able to be put on by the same person. When worn by 2 separate individuals, an arcane chain appears and secures an unbreakable bond. When this bond is made, the armguards dissipate under the skin of the wearers. This does not limit movement in any way, it feels as if there isn't even anything there. 

While these armguards are worn, Any spells or abilities that are placed on enemies (Hunter's Mark, Hexblade Curse, any other spells with approved authorization by the DM) casted by one of the wearers give the same benefits to the other wearer as well(Just the benefits, they can not also cast the spell.) Also any spells or abilities that grant temporary HP casted on one of the wearers also grants the other wearer the same amount no matter where they are. 

When one of the wearers is downed, the other wearer will know before anyone else whether or not if their partner in bonds has failed or passed a death saving throw.

These armguards can not be taken off by any normal or magical means. The only way these bonds can be broken is by the death of one of the wearers. Once one of the wearers dies, the other will know when they see the armguard reappear back on their arm. The wearer can also always hear the heartbeat of the partner if they put their ear to the arm they put the guard on.

Notes: The first of the 2 wearers