Instructions: 1. Grind or flattern the head of damaged bolt or screw. 2. Use a heavy hammer and center punch to make the centre of bolt or screw. 3. Drill into the bolt or screw in reverse using a left hand drill bit with lightweight oil. 4. Most bolts or screws come out before the hole drilling operation is finished. 5. The hole drilled will form a pilot hole for a screw extractor if the bolt or screw isn't removed out. High Quality: M35 Cobalt steel precision ground drill bits for extra durability and long lifetime Efficient Design: Stubby drill bits measure from 2-1/4" to 3-5/8" inch only, allowing access to hard-to-reach and tight spaces. 135 degree split point multi-blades drill tip for perfect self-centering and fast drilling Multi-Purpose Use: Suitable for drilling stainless steel and various hardened metals such as cast iron, titanium, bronze, aluminium, etc, perfect for removing damaged stubs, bolts and screws, or drilling a pilot hole for a screw Popular Sizes: Includes imperial sizes: 1/8", 5/32", 3/16", 1/4", 19/64" Unique Packaging: Packed in special plastic box for easy storage, imprinted with drill bit sizes for easy identification