V-Belts are identified for size according to industry standards. A combination of letters and numbers indicates the width across the top of the belt (often referred to as cross section) and the belt length. Classical belts come in five widths: A, B, C, D, and E; while Narrow belts are made in three widths: 3V, 5V, and 8V. In addition, there are the Light Duty 2L, 3L, 4L, and 5L belts.