Beyond Guardian Air by Aerus

This one is the Cadillac which combines  a buffet of processes most importantly is their patented Active Pure which has recently been proven the massively attack the Corona Virus:

Testing data conducted by an independent FDA-compliant laboratory, MRIGlobal, established a 99.98% surface kill rate of live SARS-CoV-2 virus in just 7 hours.

The 4 Levels of Purification include:
Ion Generation
ActivePure® Technology
Carbon Filtration
Waterproof Polypropylene Filter

https://www.beyondbyaerus.com/Site/Products