The Positivia COVID-19 Ag Rapid Test External Control Kit is intended for use with the OnSite COVID-19 Ag Rapid Test.Enough materials for performing 10 sets of control tests Using the same test procedure as clinical specimens for quality control consistency and user convenience. Reconstituted COVID-19 Ag Positive Control is stable at 2-8°C up to 28 days. Negative control also serves as buffer to reconstitute positive control. Lyophilized format.