Astraalbner

this is a two of a kind version of the Amulet of back-step, these amulets, have one red stone and one blue stone at a time, and do not have the switch to turn red to blue, or blue to red, but instead, a button that creates a portal to the astral plane, and only if you press the button again, the portal closes (yes, you can chop off someone's head with a portal). 

Notes: must be attuned by an artificer, or someone who could've been a good artificer