Peter Thomas Roth Instant FIRMx Glow Filter Priming Serum is a serum that uses illuminating minerals and diamond powder to instantly illuminate skin for a more lifted and defined look. It also uses 5% Actigym Clinical Contouring Technology, which is a fermented marine-derived ingredient that helps sculpt the skin over time to define the appearance of the cheeks, chin, and jawline. The serum also blurs imperfections and leaves skin looking radiant and perfectly prepped for makeup.