SRD:Well of Many Worlds

Well of Many Worlds: This strange, interdimensional device looks just like a ''portable hole. ''Anything placed within it is immediately cast to another world—a parallel world, another planet, or a different plane (chosen randomly). If the well is moved, the random factor again comes into play. It can be picked up, folded, or rolled, just as a portable hole can be. Objects from the world the well touches can come through the opening just as easily as from the initiating place. (It is a two-way portal.)

Strong conjuration; CL 17th; Craft Wondrous Item, gate; Price 82,000 gp.