Specification: Shank diameter: approx. 3mm Bristle disc diameter: approx. 25mm Hole Center 2mm Material: Nylon + Aluminum Oxide Grains Package Content 6 x Radial Bristle Discs (Green) 80# Grit 6 x Radial Bristle Discs (Blue) 120 Grit 6 x Radial Bristle Discs (Red) 220 Grit 6 x Radial Bristle Discs (Gray-Blue) 400 Grit 6 x Radial Bristle Discs (Purple) 600 Grit 6 x Radial Bristle Discs (Light Green) Grit 1000# 6 x Radial Bristle Discs (Gray) 2500 Grit 8 x 3mm Mandrel Features: 1. Bristle disc for deburring, cleaning, finishing and polishing detailed parts, tiny spots and irregular areas, more effective without scratches. 2. Disc diameter: 2.5 cm, Shank diameter: 3 mm. 3. These radial bristle brushes are ideal for jewelry making, hobbies and crafts, metalworking, wood carving and DIY projects. 4. These fine grinding brushes have good elasticity and toughness. Note:Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. Since the size above is measured by hand, the size of the actual item you received could be slightly different. Thank you for your understanding.