The PHODS Specialty Helmet Clip is used on helicopter aircrew helmets equipped with Integrated Helmet and Display Sight Systems (IHADSS) to attach the cannula of the Portable Helicopter Oxygen Delivery System (PHODS) near the nostrils of the user. 
 
This clip is typically used with IHADSS & Gentex HGU-84 helmets. The clip is attached to the microphone knurled nut. 
 
NOTE: Most other helmets use the PHODS Standard Clip.