These bristle brushes can be used for polishing any type of material in the dental lab - including porcelain, acrylic, or any type of alloy. Typically used in the final polishing stages in conjunction with a polishing compound. The style of this brush is #11 standard stiff. The diameter of the brush head is 11/16” (18mm). Each brush is mounted on a handpiece shank (3/32”). Packaged 12 to a box. Made in China.