M·A·C Fluidline is an ultrasmooth gel formula that provides the precision of a liquid liner with a silkier, softer finish. It goes on foolproof with a brush (sold separately) in an easy dip-and-stroke action. Long-wearing, waterproof and smudge-proof, it's available in a rich array of colors and finishes. Non-acnegenic. Ophthalmologist tested. Dermatologist tested.