SRD:Gate Key

Gate Key: When properly operated, the gate key can be used to attune any bounded space, such as a doorway or a cave opening, to another bounded space on another plane of existence previously visited by the wielder. When two bounded spaces are attuned, an interdimensional portal springs up at each location, and the two portals are connected. When the wielder creates a pair of portals, he or she also establishes the necessary key that travelers must have to access the portal. Possible keys include nothing, a pearl, a particular hair color, or even the gate key itself. Up to sixty different pairs of portals can be attuned in this manner. Once all sixty pairs of portals are created, the key cannot create additional gates, though it may still be the necessary key to access some or all of the portals. To any creature without the proper key, the interdimensional portals are not visible (through true seeing or similar magic reveals their presence).

Caster Level: 21st; Prerequisites: Craft Wondrous Item, Craft Epic Wondrous Item, gate; Market Price: 378,000 gp; Weight: 1 lb.