The 3M™ Combination Dual Airline Back-Mounted Adapter Kit, SA-2100LP delivers air to both sides of the facepiece for a comfortable and balanced 3M™ Supplied Air Respirator System.The back-mounted arrangement keeps work area open. The kit includes 3M Breathing Tube, SA-2600, 3M Belt, GVP-127, and 3M Valve, SA-1029.