efficere 8-piece premium 1/2” reduced shank silver and deming large drill bit set in aluminum carry case, m2 high speed steel, 135-degree split point | sae inch size 9/16” - 1” by 1/16th increment efficere efficere 8-piece silver and deming drill bit set is an essential tool and perfect choice for drilling large holes over 1/2” diameter in wood, plastic, aluminum, copper, stainless steel, sheet metals and many other types of materials. constructed from premium cobalt high speed steel for dependable strength, these drills bits are built to last. featuring 135 degree split point at tip, they start cutting with self centering for faster speed and prevent walking during drilling. a superior gold titanium and black nitride dual coating finish is applied to each drill that holds up lubricant better for smoother drilling and is 80% more durable and corrosion resistant than regular black enamel finish. all the drills have a universal 1/2 inch reduced shank with tri-flat end and securely lock onto any 3-jaw chuck from all brands of power tools. set includes 8 pieces of 6” length silver & deming drill bits in a handy aluminum storage case for easy carrying and organization: 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, and 1”.