MAC's Prep + Prime Skin was one of first facial primers I used as a teenager and to this day, I still always have a bottle of this on hand. Face primer is an essential step to ensure your foundation applies smooth and lasts all day. The formula is a lightweight gel lotion to even out your skin's redness and tone.
I find that one pump is enough for an application and I prefer to use my hands to apply primer instead of a brush to warm the product up. You will see some glitter particles in the formula but by no means does that transfer at all into your skin. I believe what is does is add radiance into your skin to give it the glowing effect. This primer results in my foundation applying smooth like butter and it fills in your pores (without congesting them) to give you a beautiful and flawless finish. I've been a fan of this primer for many years so I definitely recommend it!