Fitment Brake flaring tool applicable for soft metal tubes, including copper and aluminum, works with 304 stainless steel, steel tubing. It is widely used for brake lines, fuel lines, transmission cooler lines in vehicle repairs. Features: (1) Quickly create single, bubble or double flares on 4 different sizes of tubing. Makes tubing wider to brake line end for a leak-free connection without hours of hand cramping or twisting exercises. For 3/16-inch (4.75mm), 1/4-inch (6.35mm), 5/16-inch (8mm), and 3/8-inch tubing. .