B-Dama (ビー玉 Biidama) is the term for the official marbles used for B-Daman. They are .67 of an inch, but most marbles in the world are .5 of an inch. The name is derived from the Japanese word for "marble."
NOTE: IT IS ILLEGAL TO USE NON-OFFICIAL MARBLES DURING COMPETITION.
The naming of B-Dama was changed when Battle B-Daman was released in North America to B-DaBalls. When B-Daman Crossfire was released, B-DaBalls was changed to B-DaMarbles due to safety reasons. All 3 terms can refer to glass or plastic marbles and are used interchangeably by fans.
See also: Strike Shots.