What the?? Air on or off???

[Vtach]

I open and close my own gas along with a predive breathe of my primary and backup prior to donning and again while in the water.  I feel it is important to have this in my routine so I do not become complacent.  Sorry but I would not use a device such as this.  Not that its a bad idea, it might be applicable for others, just wouldn't work for me.