The M977 cargo truck variant is the base member of the HEMTT family. The current model is the M977A4; there was no M977A1. In addition to the basic M977A0/A2/A4 cargo truck, two other variants are available. The M977A0/A2/A4 Electrical Power Plant (EPP) has an extended cargo body (6.041 m (19.82 ft) inside length) and is used to hold and transport generators for the Patriot air-defence missile system. There is no material handling crane on the EPP. The M977A0/A2/A4 Large Repair Parts Transporter (LRPT) and the basic M977 cargo truck are fitted with a light-duty Grove materials handling crane mounted at the rear of the chassis.^[7][12][13]