The Valve and Clip Assembly for the Mirage Quattro/Quattro FX Full Face Mask is a high quality kit which functions as an excellent replacement item. The valve and clip assembly attaches to the front of your mask - the valve is inserted into the elbow of the full face mask and then helps to protect patients against asphyxiation. This anti-asphyxia valve and clip are highly durable parts which should last a long period of time provided that patients exercise proper care.