Aircraft Extension Cobalt Drill Bit Size: 1/8"(Diameter) x 1-5/8"( Flute Length) x 12"(Overall Length) HSS Cobalt Material: HSS(M35) Cobalt Steel Enable Long Drilling Life and Fast Drilling Performance Surface Treament: Gold Oxided Ember Finished Treatment Keeps High Hardness of Body Shank of drill bit Split Point 135 Deg. Drilling Angle: Split Point 135 Deg. Guarantee Self-Centering and Easy Quick Penetration of metalworking and steel drilling and cutting Application: Drilling through stainless steel metal iron copper plastic and metalworking auto reparing maintenance and DIY home metal cutting Spiral Twist Flute: The drill bit is designed with spiral twist flute ensures fast chips and debris removal during drilling application Round Shank: Featured with standard round shank is vasertile with various chucking types of tool holders when drilling different material HSS Cobalt Drill Bit Aircraft Extension Extra Long Drill Bits M35 Cobalt Long Drill for Deep Hole Drilling in Steel Metal Iron with 6 Inch Overall Length