Brand New. Sealed package ⭐️ 1 fl oz / 30 ml Vitamin C Serum Please keep in Mind Posh takes 20% Low offers will not be considered. Obagi Professional-C Serum 20% is a concentrated Vitamin C serum that delivers a youthful, radiant complexion. 20% L-ascorbic acid promotes an even tone and texture Advanced form of vitamin C absorbs five times more easily than other serums Neutralizes free radicals before they can cause damage to the complexion