The 155mm BONUS (“Bofors Nutating Shell”) is a modern technology 155 mm artillery cluster round that is highly accurate for todays battlefield. It was developed in cooperation between Bofors of Sweden and Nexter of France, designed for a long range, indirect fire top attack role against armoured vehicles. Development on BONUS began in early 1985 as a study project for the Swedish Defence Material Administration, with an initial expectation of development completion by 1989 and production start by 1990. By 1990, the development completion date had slipped to 1992. The BONUS base bleed carrier shell contains two submunitions, which descend over the battlefield on winglets and attack hardened targets with explosively formed penetrator warheads. 155 BONUS is a 155 mm NATO artillery round that consists of a 47-kilogram (104 lb) heavy artillery projectile containing two autonomous, sensor-fused, fire-and-forget submunitions. After the submunition is released it opens two winglets. While descending, the submunition rotates, scanning the area below with multi-frequency infrared sensors and LiDAR that compares the detected vehicles with a programmable target database. The submunitions each contain a high-penetration EFP warhead for use against even heavy armoured fighting vehicles like main battle tanks. When fired from a 52-caliber barrel, a BONUS shell can travel up to 35 km (22 mi).