COVID-19 antibody test 1 PU * (25 pieces) from 4 PUs : one FFP2 mask per test free of charge * PU = packaging unit; 1 PU = 25 pieces; Offer valid while supplies last. PU = Packing unit; 1 PU = 25 pieces; Offer valid while supplies last. For bulk orders of 1000 or more, please contact us