There is cooling wax inside the drill body, which can cool and wet the drill bit, and it can be dry drill. and low price, high cost performance. With fine workmanship, not easy to wear and tear, very practical in use. Made of materials, durable and safe for a long time use. Though simple in design, its so practical when you use it. Delivery Quantity: 1set (6pcs) Package Contents: Only the above package contents, excluding other products. Size: 6mm: 0.6*0.6*6.6cm; 8mm: 0.8*0.8*6.6cm; 10mm: 1*1*6.6cm; 12mm: 1.2*1.2*6.6cm; 14mm: 1.4*1.4*6.5cm; 16mm: 1.6 *1.6*6.5cm (Reminder: The size is measured manually, please allow 1-2 cm measurement error) color: blue (Due to different monitors and lighting effects, the actual color of the item may be slightly different from the color shown on the picture.)