The synthetic M Layer brush is, quite possibly, the single most useful brush you will ever own. It's also serviceable for basing, washing, or anything else you could think of as far as painting your models is concerned.
As a Citadel STC brush, the bristles have been made out of the finest 100% synthetic fibres Games Workshop have ever produced, helping to maintain the ideal brush shape and prevent curling at the tip. This brush has been carefully designed to paint any level of detail you might encounter. It's an excellent companion to regular Citadel brushes, and designed to work perfectly with the Citadel Colour paint range.