Revlon Colorstay Brow Fiber Filler Gel - Dark Brown 1. Our longest lasting eyebrow filler! Up to 2-day wear! 2. Get instantly fuller eyebrows that last up to 2 days with a fiber-infused waterproof gel. 3. Thicken, fill and define your brows in a few simple swipes.Waterproof and smudge-proof.