Usage Tips:Removable and Adjustable: Use the included hex key to remove the screws and adjust the length of the countersunk holes to adjust the drilling length of screws of different lengths, improve work efficiency. Ideal for DIY, home and small woodworking projects, to adapt to different woodworking needs. Durable and Long: The drill bits are made of HSStungsten steel, the drill body is made of 45 steel substrate, it is strong and durable, sharp tungsten steel blade, fast drilling, smoother cutting, sharp and wear-resistant without burrs. Applicable Material: On hardwood and plywood, the hole is clean and well drilled, also on compressed board, plastic, MDF, pine, beech, the drill bits are sharp, also ensure a long service life and reliable performance. Applicable models: 8mm round shank countersunk drill bit set, can be firmly fixed on the drill chuck. Compatible with most models, lithium electric drills, hand electric drills, bench drills, etc. 90 standard milling angle: The wood drill bit uses a standard 90 angle to drill holes. Practical function: Use the center drill for spiral flute, which can quickly discharge the chips from the hole. It can effectively prevent the accumulation of debris and improve drilling efficiency