Balance Balls are a classic desk toy. Also known as Newton*s Cradle- the clacking of the steel balls will keep you entertained throughout the day. Pull back one or more of the balls- release them and the same number of balls will swing up on the opposite side. The balls will click back and forth until they stop... a soothing experience you*ll enjoy. This miniature set of balance balls is fun for the office and makes a great desktop gift. ***** 2.5* wide x 2.75* tall x 2* deep- balls are .375* diameter- metal frame- silver color- assembled.**