This insubstantial silver blade appears to cut through solid walls.
Wondrous Item 13,000 gp
Power Daily (Standard Action)
When you use the exodus knife to trace a doorway onto a solid object, it opens a portal into an empty extradimensional space 4 squares wide, 4 squares high, and 4 squares long.
While the door is open, anyone can enter, see into, or affect the extradimensional space. Only creatures inside the space can open or close the door (a minor action). Once closed, the door becomes invisible to anyone outside the extradimensional space. Creatures on the inside of the closed door can see out, but those outside can't see in. Creatures on one side of the closed door cannot affect creatures on the other side.
The extradimensional space lasts for 8 hours. Any creatures still in the space when the effect ends reappear in the closest unoccupied squares outside the door.
Published in Adventurer's Vault, page(s) 171.