Real Boar hair bristle brush in size small which is approximately 8 inches long.
HGTV HOME magazine from MAY 2015 ~ chose Annie's brush to be the very best brush for painting with products that were mineral or chalk based.
For me personally- I love the SMALL brush - and the medium is nice too. The LARGE brush is a big brush and can become too heavy for my hand to hold over time based on the amount of paint the bristles can hold on to since the amount of paint that the bristles hold equates to weight. But we do sell a lot of the LARGE brush!
The key to investing in tools like this brush..... is to always take care of it. Then you make an investment in them only once!
Prior to use, consider washing it a few times vigorously. This will expedite the normal bristle loss that happens with all new paint and wax brushes. Keep in mind, if you lose a hair from the brush while painting, do not use your fingers to pick it out. Using your paint brush, come at the hair perpendicularly. Using your brush, just swoop up the loose hair, pick off the brush, and then continue.
I assure you, once you have used your brush a few times, it will not lose hairs.
Now when cleaning your brushes, never soak them overnight. Since you are using Chalk Paint® just use warm water and gently rinse.