ID (mm): 51, 64, 57, 44.5 OD (mm): 76, 86, 86, 70 Overal length (mm): 155, 254, 155, 205 Specially designed to create a smoother exhaust flow better than standard flex couplers. Reduce the whistle noise caused by turbo charged applications. Relieve exhaust system stress caused by engine movement. ...