This one is known as there Maxflow Racing Bypass Valve, So far this is the worse sounding one. quite and makes my supercharger even more quite. It work like a bov but sounds wimpy. I will need to study this one some more The one page manual
Video notes:
explaining the working of that thing on the back. gereral overall
Rev meter from inside the car with shotgun mic.
Shots of inside the bov showing it working
Adjusting hard or soft to making a difference.
Pan from holding over in engine to trash can and throw it away