She mixes one drop of the Make Up For Ever aqua seal.▶ 2:58–3:01
This helps the foundation last longer and prevents oxidization so your base doesn't slowly turn darker throughout the day.▶ 3:01–3:05
She even said that this makes it waterproof enough for swimming, which completely blew my mind because I would only use the Aqua Seal to revive liners I didn't actually know. You can add it in foundation.▶ 3:08–3:10