These titanium nitride coated countersink bits are designed to last longer than regular steel bits. The titanium nitride coating provides added durability and resistance to wear, ensuring that these bits will provide reliable performance for a long time. The set includes five sizes: 8, 10, 12, 16, and 19mm, providing a range of options for different countersinking tasks. The bits have an effective 5 flute 115° countersink design, making them suitable for use on wood, plastic, and most ferrous and non-ferrous metals. The bits have 6mm diameter shanks, making them compatible with a variety of drill chuck sizes. Whether you are a professional carpenter or a DIY enthusiast, these titanium nitride coated countersink bits are an excellent choice for all your countersinking needs.