it's for both. Mainly to get the air outta the line, but people use it to bleed off some pressure too

 

The main purpose is PSI.
with proper psi consistant tune up and times are acomplished.
it also rid the air in the lines, but most use it because it looks cool.
I know a kid that has a purge, but no heater and no psi gauge!!! but yet he still purges. lol

 

damn ill be getting that here in about a month or so..nice way to scare off some rice haha

 

 

What happend to that vid of the master blaster?