EASY OUT REMOVING: It is more convenient and easy to remove the broken screw from the damaged workpiece by using the left hand drill bit which coordinates with the screw extractor. Spiral groove on screw extractor can go deep into screw to increase grip force to remove studs, screws and bolts around the house, garage or on your job project HIGH QUALITY Cobalt HSS MATERIAL: The PRESTO left hand drill is made of HSS M35 with 5% Cobalt . Compared with ordinary high speed steel of 4241 or M2, M35 cobalt material is hardened steel with excellent cutting performance, it can prolong the service life, enhance wear resistance and remove chippings clearly. Cobalt HSS are harder and tougher than other materials. The Chrome Alloy-Steel construction for strength and longevity. The screw extractor use high strength chromium Alloy-Steel for better toughness and longevity. UNIQUE DESIGN: The 118°angle in small size drills (5/64”, 7/64”) makes it easier to cut into the workpiece with small axial resistance, it can avoid the drill breakage caused by drill walking. The 135°angle with split point in big size drill (5/32”,1/4”,9/64”) helps the drilling in heavy duty in harder metal. CONVENIENT ORGANIZATION AND STORAGE: Come with a metal index case, convenient to use and carry. SET INCLUDING: 5pcs alloy steel screw extractors and 5pcs HSS Cobalt M35 left hand drill bits. Screw extractor includes #1, #2, #3, #4, #5. Left hand drill bit model includes 5/64", 7/64", 5/32", 1/4", 19/64". 10pcs Screw Extractor and Left Hand Cobalt Drill Bit Set