Auction Detail Amazon.com: CERROPI Newtons Cradle Pendulum with 7 Balls, Classic Swing CERROPI Newton Cradle Balance Balls, Newton Pendulum with 7 Balls CERROPI Newton Cradle Balance Balls, Newton Pendulum with 7 Balls. Features SUPERIOR QUALITYOur newtons cradle made of 8. 1mm chromed metal steel bar, 20. 1mm bearing steel,high impact nylon, ultra thin nano technology provide extremely durable oscillatory support, durable for long time use. Pursuit of craftsmanship spirit inspired us to continuously produce high quality goods SCIENTIFIC DESIGNCERROPI newton's cradle adopt scientific design,keep the pendulum balls perfectly lined up,make it possible to swing 50s+. Perfect demonstration of the scientific law of momentum conservation and energy conservation WIDE APPLICATIONThis newton balls can be used as office desk gadgets toys to relieve stress; as teaching aid,teaching science intuitively; as toys for family activities, to inspire your child's creativity EXQUISITE PACKEGINGWe use individual wrapping paper to protect each ball and secure it in foam shockproof material,Perfect for Christmas gifts, Thanksgiving gifts, birthday gifts,Mother's Day gift,Father's Day gift,Valentine's Day gift etc. WARRANTY & NOTICE1 YEAR warranty, If any piece breaks we send replacement balls, strings and plug to you. Messages reply within 12 hours. NOTE: clean the ball thoroughly before using for the longer swing time,one extra ball and a silky soft cleaning cloth are included in the package Product Description CERROPI Newton Cradle Balance Balls, 7 Ball Newton Swing, Decorative Physics Gadget for Desk, Marble Base, 11 inch, 50+ Sec Swingtime