SAWSAVVY 3/16 to 1-3/8 Inch Step Drill Bit Straight Grooved Double Fluted, M2 High Speed Steel Drill bits for Hole Drilling in Stainless Steel, Copper, Aluminum, Wood, Plastic About this item [M2 HSS]: Cuts A LOT MORE CLEAN holes and much EASIER than average step bits. In general, M2 has 50% more Tungsten and 150% more Molybdenum, both of which are key elements in improving durability. Our additional Vacuum heat treatment and Nitride surface hardening treatment make the performance even better. [Non-stop]: Our Polished Steps and Size Highlights let you able to see target hole size during drilling. No need to stop in the middle of the drilling and check. Save you time and hassle. [Easier | Faster | Cleaner]: With our high-accuracy CNC processing and several optimized design details over the years, our design cuts EASY, FAST and CLEAN, outperforming the average ones on the market. [Heavy duty]: Cuts holes on Stainless steel, Hardened Metal, Mild steel, Galvanized steel, Aluminum, Copper, Plastic, Wood, or anything that has similar or lower hardness as these materials. Up to 12ga /2.7mm thickness for Stainless steel. [Multi Hole Sizes]: No need to buy a kit. This one step bit comes with 6 marked sizes so you can drill 6 different hole sizes, saving you time and effort to change bits. Marked sizes including: 3/16", 7/8", 1-1/8", 1-7/32", 1-1/4", 1-3/8".