As described on her site, each brush roll is made from medium weight cotton and has a lot of durable stitching on the inside. There are pockets with various sizes to hold different size brushes, and a large flat flap covers the brushes when rolled and will not poke out at the top. There's also two handy thick strings to help hold the brush roll together. You can also easily clean it in the washer, or use mild soap and water.
She also has a small brush roll (8 pockets) for $16.99 and the large brush rolls (like the one featured here with 16 pockets), for $20.99. Definitely check her site out for more pics and info because she has tons of awesome stuff!
Large makeup brush roll approx. measurements:
approx. width = 18.5 inches (47 cm)
approx. height = 14.5 inches (37 cm)