This is the OTS Ambient Breathing Valve (ABV) for Specturm Mask Features: Fits: OTS Spectrum Full Face Mask (FFM) see SKU&';s: OTSSFM, PCKOTSSMB2 Breathe Ambient Air at Surface Conserving Tank Air Simple to Use Operation: to Breath, Rotate Valve Counterclockwise, Close Valve: Rotate Fully Clockwise NOT a Snorkel! Check Valve: Allows Air-to-Enter Valve Only Air is Exhaled-Out Regulator Check Valve: Prevents Gas from Escaping via ABV If Open Underwater The most anticipated accessory for the Spectrum Full Face Mask is finally here! The Ambient Breathing Valve (ABVA(R)) allows a diver to breathe ambient air while at the surface, thus conserving tank air!