This clipper brush and spring assembly part number 042584-025 consists of two rectangular carbon brushes with small plastic caps on them, and two tiny silver springs. Both brushes should be replaced at the same time. Fits Oster A5 clippers. Carbon brushes should be changed every 300 to 400 hours of use (three to six months) or when worn to 1/4-inch. Carbon has a small O on it to determine when brushes should be replaced. If O is worn halfway down, replace immediately. Measures 3-1/2-inch length by 2-2/7-inch width by 2/7-inch height