ROKR - Wheeled Siege Artillery - Medium LevelDescription Specification Package includes 5 table tennis balls (Diameter: 40mm) Product Size: 320*130*210mm Wood Pieces: 158 pcs Weight: 0. 69 kg Assembly Time: 3H ROKR Wheeled Siege Artillery is produced by the elastic force provided by the rubber band (which may be changed to a spring or other structure) and the cooperation between the parts replaces the battery and realizes the manual launch. For the round barrel, the small wooden slats used are