Gels are not only lightweight but feel silky on this skin. This gives foundation a good base to grip on and your foundation will apply more evenly. I personally love the cooling effect they have on my skin. While you can apply gel primers with a sponge or brush, many people like them because they're best applied with your fingertips. As long as gel primers aren't too thick and tacky, I can wear them under foundation. I personally prefer blurring and poreless primers for under makeup since I have texture issues from acne scars.