The Reo is a bottom-feeder, which is a completely different design than a ProVari. Many people consider it to be the ProVari of bottom-feeders due to its durability, performance and the wonderful support of Reomods (Rob) and the Reonauts sub-forum.
A bottom-feeder is a very simple device. It's a box mod with a little bottle of juice inside. You squeeze the bottle (called "squonking") and the juice goes up a tube and feeds into the bottom of an attached atty. It is the equivalent of dripping when it comes to flavor, since it is essentially dripping upside down. Since the systems are so different, the Reo complements the ProVari very nicely.
There is the skynet to convert the provari to a bottom feeder - i dont know if anyone here has one, and if they are any good?
There seems to be very little info about them - i think they are made by an italian firm, and the only youtube demo of one i could see was in italian...

Chalice Skynet Provari - YouTube