Tool set for glass engraving (4-piece)

4-piece glass working set\n2 diamond grinding bits and 2 silicon carbide grinding bits. For engraving, grinding or frosting glass. Diamond bit 1: ball ? 1.0mm, diamond bit 2: ball ? 1.8mm, silicon carbide bit cone 3/2 x 5mm, and bullet 2/2.5 x 7mm. All shafts ? 2.35mm.