The 3M™ Versaflo™ Heavy Duty Tight Fitting Breathing Tube, BT-64 is designed to be used with 3M™ Full Facepiece Respirator, FF-400 Series, 3M™ Full Facepiece Respirator, 6000 Series, and 3M™ Full Facepiece Respirator, 7800S Series and the 3M™ Versaflo™ Powered Air Purifying Respirator, TR-600.