Hydrogel Face Mask. For those of you who want great, instant results versus regular semi-paper sheet masks, or even cotton sheet masks. These premium facial masks are the most popular ones in the hydrogel category. The main difference between sheet masks and hydrogel masks are the materials. The Korean gel masks are made with water and in a thin gel form. They have the ability to lock in moisture much better than sheet masks. We only carry the most prestigious and reasonably priced line of Hydrogel facial masks in today's competitive beauty market.