Sturdy and wearresistant construction Made of carbon steel with a blackened surface for enhanced wear resistance. Fully hardened by temperature quenching to achieve higher hardness, helping keep the cutting edge sharp, reduce wear, and extend tool life. 90degree chamfering for accurate holes Cutting angle of 90 degrees creates a precise 90degree chamfer on nonmetallic soft materials such as wood and plastic. Enables accurate hole openings and clean edge trimming. Note: not suitable for chamfering metal. Fiveflute design for reliability and efficient debris removal Fiveflute structure minimizes vibration during cutting and improves tool stability. Debris is efficiently discharged, keeping the work area clean and facilitating hole clearing to boost work efficiency. Multispecification set for versatile applications 3piece countersink chamfer drill bit set includes 12 mm (0.47 in), 16 mm (0.63 in), and 19 mm (0.75 in) sizes. Different chamfer sizes accommodate various workpieces, enhancing overall efficiency. Applications and use scenarios Woodworking: create clean, accurate holes with precise 90degree chamfers for screws and dowels, improving assembly quality. Plastic panel and enclosure fabrication: deburr and trim edges for smooth finishes and precise fitment. DIY and general softmaterial work: prepare openings and chamfers on soft boards and plastic parts to ensure neat joints and professional results.