license produced variant of the M109A2. In the 1960s, the South Korean Army received M107 and M110 from the United States. However, the number of these self-propelled guns was insufficient to counter rapidly-growing North Korean artillery capabilities. In the 1970s, South Korea began mass-producing towed howitzers locally, but intelligence reports of North Korean 170 mm self-propelled artillery forced South Korea to look for a new self-propelled artillery system. In December 1983, the ministers of defense of the United States and South Korea signed a MOU to co-produce M109A2 in South Korea using American technical data. The United States delivered two completed M109A2s to South Korea for operational review, and the Agency for Defense Development began to translate the data package and created field and maintenance manuals for soldiers. South Korea wanted to produce every part of the vehicle domestically; however, due to the amendment bill by Rep. Samuel S. Stratton of New York, which established a limit for foreign military technology cooperation, the turret and the M185 cannon from Watervliet Arsenal were imported from the United States. Compared to the M109A2, besides 63 percent of parts being produced locally, K55 has a driver's night periscope and light exposure minimization device to enhance night-time operations as well as additional radio systems. The vehicle has an NBC protection system and halon fire extinguishers. A total of 1,180 K55s were produced between 1985 and 1996. The vehicle's name was changed from KM109A2 to K55, originally a code name from the Samsung factory. In November 1990, the United States and South Korea signed an agreement to allow South Korea to supply M109 parts to third parties. In May 1997, during the Security Cooperation Committee held in Washington D.C., South Korea requested that the United States revise the MOU to export complete K55s, originally intended for domestic use only. South Korea was expecting to export 72 K55s and four ammunition support vehicles to Brazil for $160 million over Belgium's offer, but the United States Department of Defense declined the request to avoid an arms race in the region. In May 1998, the South Korean military began operating a K55 simulator to boost artillery operator training. The simulator took a year and a billion KRW budget to develop. It is expected to save 150 million KRW per year per device. K55A1 The K55A1 is a South Korean overhaul and modernization of the K55, augmenting the proven