When used in a commercial or defence department application, often a 75mm ring type towing eye is requested. This style of coupling is similar in function to ball type couplings (fixed and override) but instead of the connection to the tow vehicle being a standard 50mm ball, the connection is a 75mm inside diameter ring and this attaches to a pintle hook fitted to the tow vehicle. These types of couplings are typically used in applications where the tow vehicle is a heavy commercial truck.