Q: 【How about quality assurance & after-sales service? 】 A: We are committed to providing customers with high-quality products and excellent services. If you have any questions about product specifications and usage methods, you can contact us; if you have not received the package, the products damaged due to the logistics, or you are not satisfied with the product itself, please contact us, we will give you satisfied reply and solution within 24 hours. Looking forward to your purchase and experience of our product Specifications: Material: High-speed steel Type: Twist drill bit Diameter: 2mm, 3mm, 3.5mm, 4mm, 5mm Length: 150mm~160mm Package Includes: 5 x Drill Bits