1st Stage Pre Filter:
A pre filter is the primary layer of filtration that collects large particles before they reach the HEPA filter. Eliminating these larger particles, dust and hair extends the life of your HEPA filter. Occasional vacuuming of the exterior of the unit will help extend life of the filters. Frequent pre filter changes will also prolong the HEPA filter life.
13” X 13” 1st Stage Prefilter
30/Case
Use these with Aerospace America 400& 500 Mag.
16" x 16" 1st Stage Prefilters
1st Stage 16" x 16" Replacement Pre-Filter For Air Machines (Novatek, Aerospace America)
1 case consists of 30 prefilters.
24" x 24" x 1/2" 1st Stage Prefilters
(30/Case)
This first-stage, polyester pre-filter designed for the Phoenix Mini-Guardian is 24-in. x 24-in. x 1/2-inch. Order in quantity if your Phoenix is in constant use, as this filter should be changed daily
13” X 13” 1st Stage Prefilter 
24" X 18" 1" 1st Stage Prefilter