Product Description Material: high speed steel Surface treatment: Titanium plating Applicable to: workpieces with a hardness below 28, such as aluminum parts, iron plates, plastics, PV panels Size: 2-5 (the hole is in the range of 2MM--5MM, the handle is 6MM, the diameter of the head is 9.7MM) 5-10 (the hole in the range of 5--10MM, the handle is 8MM, the diameter of the head is 14MM) 10-15 (the hole in the range of 10MM-15MM, the handle is 10MM, the diameter of the head is 21MM) 15-20 (pour the hole in the range of 15MM-20MM, the handle is 12MM, the diameter of the head is 28MM) Color: golden Quantity: 4 pieces Package content: 4 pieces * chamfering device 1. High quality material - Made of high-speed steel (HSS) 4241, this countersink drill set has a high red hardness and wear resistance, high cutting speed, sharp cutting edges and high toughness. The surface is titanium coated to increase wear resistance and durability. 2. High Efficiency - Countersink set with high precision and clarity, 90 degree chamfering, strong chamfering force, smooth and flawless, save time and effort, improve work efficiency for domestic and industrial operation. 3. High security performance - Countersink kit set with internal chip removal to prevent metal flying phenomena to ensure safety. 4. A variety of specifications - Countersink metal set has 4 kinds of specifications to choose from, to meet a variety of needs, more convenient operation. 5. Other applications - Countersink HSS set is suitable for cutting metal, wood, plastic, aluminum and thin iron. Great for drill operations.