Pentashield

A pentashield was a five-layered shield-generated field suitable for small areas such as doorways or passenges. A large pentashield could be generated but it would become increasingly unstable with each successive layer that went up.

They were virtually impassable to anyone not wearing a dissembler that was tuned to the same codes as the shield was tuned. A pentashield set up in such a way was also known as a Prudence Door (Pru-Door) or Prudence Barrier (Pru-Barrier), and such a configuration were used to facilitate the escape of only selected people, who were often under pursuit.

The Baron Harkonnen's bedroom was fitted with a pentashield so that anyone who saw him would have to stand, blocked by it, until the Baron deactivated it, and then reactivated once they came in.