This 3M Adflo Powered Air Purifying Respirator (PAPR) has a stackable feature, which means that the 3M Adflo Organic Vapor/Acid Gas (OV/AG) Cartridge 15-0399-99X02 can be stacked onto the high efficiency (HE) particle filter for additional protection against certain organic vapors, sulfur dioxide, chlorine, and hydrogen chlorine, and hydrogen chlorine vapors. Audible and visual alarms signal low airflow and low battery charge. Its slim profile design provides wearers to go into tight spaces.  The 9002X Welding Helmet features an extra large viewing area combined with advanced electronics delivers the most versatile auto-darkening filter ever.

FYI - Numerous health problems can arise from breathing welding fumes. NIOSH studies show that welding fumes can cause bronchitis, airway irritation, lung cancer and many other health problems: 

Steel/Manganese Alloys can cause Pneumoconiosis, Siderosis, and central nervous system damage.
Stainless Steel can cause Pneumoconiosis, kidney disease, lung irritation and cancer.
Aluminum causes respiratory irritation from ozone.
Ozone can lead to respiratory irritation and congestion, bronchitis and headache.
Phosgene can cause respiratory irritation, anoxia and pulmonary edema