Austin Air HealthMate Standard Pre-Filter 2-pack is Austin Air original PermaFilt replacement pre-filter.
Austin Air HealthMate Standard Pre-Filter fits Austin Air HM400 Series air purifiers including:

• Austin Air HealthMate HM400
• Austin Air Allergy Machine HM405
• Austin Air HealthMate Plus HM450
• Austin Air Pet Machine HM410
• Austin Air Bedroom Machine HM402
• Austin Air Immunity Machine HM444

Austin Air Pre-Filter is available in two colors:

• Black - for units in Black, Midnight Blue, Graphite colors
• White - for units in White, Sandstone, Graphite colors

Austin Air Pre-filter is a first stage of Austin air purifier air filtration system.
Austin Air pre-filter traps large dust and dirt particles and protects True HEPA filter from faster contamination.
The pre-filter can be vacuumed right through the metal mesh of the air purifier housing with a soft brush.
The Austin Air pre-filter's lifetime under normal residential conditions - up to 12 months.