|Precision steel micro-bearings.|
We think these balls are about 1/32-inch diameter. Ed Pegg reports that these particular balls were accidentally magnetized by noted physicist Stephen Wolfram, making them unsuitable for Ed's experiments.
Source: New England Miniature Ball Corp
Contributor: Ed Pegg Jr
Acquired: 15 April, 2002
Price: $5/1000 (which is not a lot of bearings)