国产亲妺妺乱A片,日韩高清AV,三级片不卡AVAV,性爱AV高清,亚洲无码影视

Diamond segment and grinding wheel products are made of synthetic diamond and a variety of metal powders as a bonding agent. They are formed by cold pressing and hot pressing, and are not easy to fall off during use. It is assembled on various professional grinding wheel processing machines for the efficient grinding and polishing of the surface, inner hole and outer circle of grinding wheel products. It has the characteristics of good sharpness, long service life and high work efficiency.