These micro-tube brushes are manufactured to diameters most popular to industry throughout the country for applications such as cross-hole de burring and honing of valve bodies and fittings for gas, air and hydraulic applications, honing and removal of tool marks in die work, de burring of all manner of drilled or cross-drilled, bored or reamed holes in delicate work requiring high quality internal surface finishing, honing and de burring. All type "D" brushes are filled with 1000# grit silicone carbide abrasive charged .