This is similar to the Isolated feature, except the lair is sealed off from the outside world rather than isolated by geographic location. It may be a structure with no doors, windows, or other outside access, or behind some sort of barrier. Only the lair’s owner and designated guests may enter, although the GM should determine means by which trespassers might do so, including effects like Dimensional Travel, Insubstantial, Permeate, and Teleport
References[]
D20 Hero SRD Installations Article- http://www.d20herosrd.com/7-gadgets-gear/installations