... has passed the ISO9000/2000 3.coal mining bits 1.We can supply all kinds of RUIZUAN ... brand coal mining bits, sleeves and holders which have high strength, high ... engineering etc;3.We can design and produce different bits according to different hardness of rock to satisfy customer ... cutter drums.5.We can supply the following Bits and Holders:U82,U84,U85,U92,U94,U95, ...