1. High-Performance Drilling: The 3PCS external cooling carbide drill bit set features a non-standard diameter of 3.00, 4.0, and 5.0 mm, ensuring reliable performance for various drilling tasks. (3x14x50xD4, 4x18x50xD4, 5x20x50xD5) 2. Durable Solid Tungsten Construction: Made from solid tungsten steel, these drill bits provide enhanced durability and extended service life, suitable for both professional and DIY use. 3. Effective Cooling Design: Equipped with an external cooling structure, these carbide drill bits help maintain optimal operating temperatures, improving cutting efficiency and tool longevity. 4. Versatile Application: Ideal for use on multiple materials, this 3PCS carbide drill bit set works effectively on metal, wood, and plastic, offering flexibility across a range of projects. 5. Precision Engineering: Each bit is precision-manufactured to ensure accurate hole placement and clean drilling results, especially for applications requiring non-standard diameters. Color: As shown Material: Tungsten steel Package Contents: 3 x External cooling carbide drill bit Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the actual product. Measurement may vary by +/- 1-3 cm.