I would rule that the inside of a Portable Hole (or any other extradimensional space) is not 'on the same plane' as the outside. Sorry 'bout that.Ring Gates: These always come in pairs—two iron rings, each about 18 inches in diameter. The rings must be on the same plane of existence and within 100 miles of each other to function. Whatever is put through one ring comes out the other, and up to 100 pounds of material can be transferred each day. (Objects only partially pushed through and then retracted do not count.)