As of 2017[update], it has been in use for over 60 years and is used on the Dillon M134D Minigun, M60 Machine Gun, FN MAG/M240, Mk 48, MG3, HK21, MG5, UKM-2000, K16, SS-77, and Negev NG-7, among others.The left side of a single link has a semi-circular loop which holds the main body of the cartridge case below the shoulder, and an extension on the right that forms two similar loops which were designed to fit in between the two right-side loops of the next link, and which have a small metal tab that extends down to the cartridge base and fit into the extraction groove of the case.The feeding pawl in the gun would pull the belt to the right as the gun was fired or cocked, sending the loose link out to the right side of the receiver, where the expended case was also ejected, normally separately from a different ejector port to the link.[3] The links often have an extra anti-corrosion surface treatment, generally (oil impregnated) black phosphate, and can be collected and reassembled by hand with fresh ammunition, but in practice this is not commonly done as it is labor-intensive, and the inexpensive links are considered disposable.Sometimes the ejected link pieces are collected to avoid littering the interior of aircraft and vehicles or reuse.