Venters are man-made machines that enable the user to travel to different dimensions.
Venters are fueled by Aether crystals, which can be found in almost any dimension, and vary in size and shape, but are almost always tubular and made out of metal. The user goes inside, and when the Venter reads that a living creature is inside of it, a rift is triggered, and the machine transports them to a random dimension. Very few people have managed to obtain these machines as they are not very common, and are hidden from the public.
The first Venter was created by Dr. Lance Fielding of Venter Labs in 1999, who mysteriously vanished a year later. There is still no way to control which dimension to travel to, which can end very badly.