Excellent for illustrating Newton's Third Law of Motion and the principle of Conservation of Momentum. The five polished metal balls with thin bifilar suspensions on a unique support design provide for better results and stability. Additional Info: Excellent for illustrating newton's third law of motion and the principle of conservation of momentum. The five polished metal balls with thin bifilar suspensions on a unique support design provide for better results and stability. Package Size(L x W x H): 5.5 X 6 X 7 (IN) Categories: Mechanics, Kits HTS Code: 7326.90.8588 UNSPSC: 6.01046e+007 Country Of Origin: CHINA