When towing with heavy commercial trucks, higher loads or driving over rough and uneven Australian terrains, this ring coupling used in conjunction with a pintle hook, helps to secure your trailer and suits Australian Standard AS4177 as it states the 50mm tow ball to have a maximum capacity of 3500kg loaded trailer mass. This high quality and durable 75mm ring coupling is 6000kg rated with a D-Value of 45.5kN