Кисть in Russian is brush. It declines as such:

Fix this for end stress in the last four plurals.

It can refer to a cosmetic brush, a brush to paint a room or in this instance I am referring to it as an artist brush. Brushes come in all shapes and sizes. Brushes with smaller or less bristles are usually used for detail and small areas such as details on a car or eye while the larger ones are for larger areas such as backgrounds. A round brush allows you to paint fine points while a flat one is more versatile and can be used for broad strokes and thin ones. A fan brush is usually used for blending colors. Other forms of paint brushes include mop brush and sword/striper brush. There are different brushes for different mediums; watercolor brushes are different than acrylic brushes. Thicker brushes hold more paint and are better for wet painting such as water coloring, while the thinner brushes are better for dry painting because they hold less paint. The article which I found useful on paintbrushes is: http://painting.about.com/od/artsupplies/ig/Intro-to-Art-Paint-Brushes/. It also gives advice on cleaning, the ways to preserve your brushes, etc.