The HealthMate Plus HM450 is identical to the standard HealthMate, but the carbon in the filter is impregnated with a special blend of potassium iodide for additional adsorption of VOC chemicals such as formaldehyde and ammonia. This "SuperBlend" of carbon is the only difference between the HealthMate Plus and the HealthMate. 

360° 4-Stage Filtering System:

The Austin Air 360° design draws air into all sides of the air purifier, passing it first through an outer pre-filter and then a main filter that combines three additional stages of filtration:

• STAGE 1: Large Particle PermaFilt Pre-Filter (wraps around main filter)
  Cleanable re-usable prefilter traps large particles easily seen by the naked eye (dust, hair, lint, pet dander, etc) while prolonging the life of the main filter. Easy to maintain - simply vacuum clean monthly from the outside of the unit. 
• STAGE 2: Medium Particle Pre-Filter
  Removes additional small to medium sized particles (mold spores, pollen).
• STAGE 3: 15 lbs Carbon / Zeolite with Potassium Iodide (SuperBlend)
  Activated granular carbon/zeolite is impregnated with potassium iodide for additional adsorption of VOC chemicals such as formaldehyde and ammonia.
• STAGE 4: 60 sq ft Certified True HEPA filter media
  This final filtration stage contains 60 sq ft of medical-grade True HEPA pleated filter material. Traps up to 99.97% of particles as small as 0.3 microns that pass through the filter.

Specifications:

• Room Size: Up to 750 square feet
• Dimensions: 14.5" W x 14.5" D x 23" H.
• Weight: 47 lbs.
• Fan Speeds: 3.
• Fan Rating: Speed 1 - 75 CFM, Speed 2 - 200 CFM, Speed 3 - 400 CFM.
• Decibel Levels: Speed 1 - 39.8 dB, Speed 2 - 55 dB, Speed 3 - 64.5 dB.
• Energy Consumption: Speed 1 - 56 Watts, Speed 2 - 83 Watts, Speed 3 - 132 Watts.
• Power: 120 V / 60 Hz; 1.2 Amps, 135 Watts.

Features:

• Easy Operation - Just plug it in and turn it on! Simple manual knob control gives you a choice of 3 fan speeds. 
• Easy-Roll Casters - Large built-in wheels allow you to quickly and easily roll your air purifier from room to room for cleaner air anywhere you need it.
• No costly 3-month pre-filter replacements - simply vacuum clean the pre-filter from the outside of the unit once per month.
• Steel housing with a selection of powder-coated paint colors.
• Five Year Mechanical Warranty: The HealthMate Plus HM450 is warranted to be free from defects in material and workmanship under normal residential use for five years from the date of purchase.
• Five Year Pro-Rated Filter Warranty: The Austin Air filter can last up to 5 years, but you may need to change the filter more frequently depending on usage and environmental conditions.  With continuous 24/7 use, average filter life expectancy is about 2-3 years (the carbon will get fully saturated before the HEPA filter). Therefore, Austin Air offers a pro-rated filter warranty with discounted pricing available should you need to replace your filter before five years. 

Manufacturer's Literature [PDF]:

Austin Air Owner's Manual
Austin Air Filter Replacement / Pro-Rated Warranty