Flowflex COVID-19 Antigen Home Test And 10 Pack of KN95 Protective Face Mask – Limit 10 per customer – for only $19.99!  The Flowflex COVID-19 Antigen Home Test is a rapid test for the detection of SARS-CoV-2 antigens in anterior nasal specimens. It is intended for self-testing use. COVID-19 is caused by a coronavirus called SARS-CoV-2.