Vacuum cube
From wipipedia.org
A vacuum cube is similar in function to a Vacuum Bed but varies in execution in that the latex sheeting is stretched across a three-dimensional frame instead of the vacbed's two-dimensional frame.
There are two main variations of the vacuum cube design, an actual cube that has the user on all-fours with their head sticking out an access hole and a model deemed the 'Trifecta' which is a triangular (prism) shaped stand-up frame.