MAC Pro Longwear Fluidline Eye Liner Gel in the shade "Blacktrack" is a popular eye makeup product from MAC Cosmetics. It is an eyeliner gel that comes in a small glass pot. The weight of the product is 0.10 oz or 3 grams. MAC Pro Longwear Fluidline is known for its long-lasting and smudge-proof formula, making it ideal for creating precise and defined eye looks. "Blacktrack" is a specific shade within the range, and it is a deep black color with a matte finish. The gel liner is designed to glide smoothly on the eyelids, allowing for easy application and intense pigmentation.