This is The Army Painter Warpaints Fanatic: Eternal Hunt - 18ml Acrylic Paint

Warpaints Fanatic paints are an easy to use, high-quality acrylic paint with unsurpassed coverage and intense pigmentation. It is set in a premium resin base with proprietary stabilizers, making it possible to thin it down to extreme levels while retaining pigment dispersion.
Each paint is part of a Flexible Colour Triad System: a segment, or family, of paint colours that are made using the same root colour. Inside each Flexible Colour Triad are six colours that range from dark to light with a consistent hue. With this system, you can easily select paints that create a natural colour progression on your miniatures.
Warpaints Fanatic is easy enough for a beginner to use, fast enough for a gamer, yet capable enough for the best painters in the world.