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NEW Atmos-Tech MicroThermics HEPA Filter 24x48x3-1/2" 1940 cfm + 12 Pre Filters
What stands out about the 2N, 8N, 9N 1939-1950 is the thick steel construction that withstands abuse.
Atmos-Tech H2472C00-AAAABAA HEPA Filter 24 x72x5-7/8" 2104 CFM @ 1.0 WG NEW
I used the CPC2G Ceramic Pourable Compound to restore a vintage ceramic lamp base.