Medium Syntec Chalk Brush Heirloom Traditions has developed our own version of a synthetic fiber brush. Our Syntec Chalk Brush fibers are a hybrid between synthetic and natural boar's hair. We've specially designed these brushes to be non-shedding with tapered, thick bristles, to hold the weight of a chalk style paint, on a comfortable, coated handle. Our medium size brush is just the right size for a wide variety of products.