Amulet of planes is mainly used by astral travelers. It was not crafted on the material plane and is usually passed down or acquired by ‘other means’. The amulet has four encased stones each depicting the elemental planes which are covered by metal and the amulet only uses. Often the amulet only showcases something that is personal to the craftor or inheritor. The four elemental planes apparently are the birthplace of life. Apparently to enter them requires specific combinations. Then some speculate that all 4 crystals are required to enter the material plane, implying the material plane is a byproduct of the elemental planes. Earth, Air and Water seem to be linked with the Feywild. Fire, Earth and Water with Shadowfell and Air, Fire and Water for the Ethereal. Given the combinations people speculate more planes than what we know of truly exist. The amulet of planes requires great intellect to control fully. Apparently great mental strain takes hold of the user after use on going to places they can clearly invision in their minds. Often the strain becomes too much and they’re thrown into a plane they’ve never visited before. This implies a risk or a strain on the channeler of the amulet, that perhaps it was created or intended for creatures of greater ability than mortals. The gith have been using devices that imitate the inner workings of the amulet of planes to bring in their war ships. If this is truly from other planes or simply far, far away is unknown but it is believed that given their flying capabilities it must be from another plane otherwise they could simply fly to the destination. The mechanism has been accounted for but never fully recovered. They seem to degraded over time while in this plane of existence and the gems used seem very unstable, their power seeping out and evaporation within days if not hours of being discovered.  The leading theory is that they’re used as an anchor point, a place where another device can home in and make a specific portal to. How this is exactly done is unknown, but the item alone does not follow the normal rules of a Amulet of the Planes, as it is not with the object or person travelling, however is the location it will arrive. This implies some sort of advanced technique using two combinations of a device to ensure pinpoint accuracy. This has lead one researcher to believe that the elements themselves are not the only factor on where you end up, but the potency or composition of each crystal might matter in the location, meaning that two amulets that share crystals of the same density, power and arrangement might share a sort of connection and allow transportation from one to another.