DMM makes yet another innovation combining a wire gate carabiner and a pulley. This piece of gear is rated and certified to perform both jobs that normally take two pieces of gear to accomplish.
The Revolver works by dissipating the energy of a fall over a longer section of rope, the wheel turning until it reaches 11.5kN.
The Revolver reduces rope drag. The Revolver simplifies setting up haul/pulley systems on land or on water. Most importantly it reduces friction allowing the rope to do its job of absorbing the fall so that the falling leader will have a softer catch.
If you don't believe me, buy one and use it yourself.
As the old story goes, don't knock it until you try it.

this biner goes against the rules of KISS

if you make something complicated, its only more likely to screw up...etc etc

[url=http://www.rockclimbing.com/forums/viewtopic.php?topic=59403&forum=40] here's it talked about in a post[/url]