It's has a straight silicone brush with medium length bristles that are longer on one side. The brush deposits a lot of product in one swipe. You get plenty of volume and length, but the bristles can't cope with definition. The more I try to fix it, the more it starts creating a spidery lash effect. I didn't keep it long enough to see if it improves as it thickens, mascaras usually do, but when it's new, it's not great at definition. It's a regular formula that comes off easily, but it doesn't have hold when it comes to my stubborn lashes.