This extensive set features tin-coated HSS drill bits designed for high-speed drilling where the coating helps manage heat, ensuring durability and performance. The solid ground construction provides enhanced strength and longevity. Tin Coated : For use at high speeds, enhancing durability and strength. Solid Ground HSS : Ensures excellent cutting efficiency and durability. Comprehensive Set : Includes 170 pieces. Sizes : 10 each of 1.0 - 8.0mm in 0.5mm increments 5 each of 8.5 - 10.0mm in 0.5mm increments Storage : Supplied in a strong metal carry case for easy organisation. Brand : PTI