1. Set Contents: The hole brush in the set has a width of 0.39, 0.47, 0.59, 0.67, 0.75 inches (8, 10, 12, 15, 17, 19 mm), so you can choose the right size according to your needs. 2. Material: This product is a tube brush made of high quality stainless steel and copper. Can be used for metal and non-metallic materials, tip parts for mini routers, fit your polishing needs. High abrasion and corrosion resistance, help to grind and remove burrs of various metal holes. 3. 【Practical Design】:The steel wire channel brush is designed to easily enter into tight holes and restricted areas, and can be applied to ports, pipes, bearings, rust removers, cylinders or other narrow cleaning requirements. 4. Rotary Tools: Can be used with mini routers, routers, electric drills, etc. Clean metal surfaces, easily remove stubborn stains with high hardness 5. 【Suitable Occasions】These wire bore brushes can be applied to the car, garage, office, kitchen, and are perfect for cleaning and polishing, painting or removing rust in automotive, manufacturing, machining, and smitting applications.