If you are talking about the "All in one valve" that Don Jackson came up with, a lot of the big teams are running it now. (Kalitta's , Forces, Head etc). Instead of using an AJ Valve (which improves response at the hit and better reaction times), a Slide valve (which regulates the amount of fuel from the hit until about 2.5 seconds), and a BDK Valve (which regulates fuel volume from around 1/2 track to the finish line),it can all be accomplished with the All in one Valve. A lot simpler, less parts and a 10 or so lb weight savings. You can actually draw in your fuel curve using air pressure to custom tailor your fuel curve. Del did a lot of work with Jackson and is a reason a lot of teams are running it now.