HSS Spiral Grooved Step Drill 1/4~1-3/8"Features :No need for a pilot holeTitanium coated to reduce friction and run coolerHigh speed steel，durable.HSS Drill Bit Set For Wood， Plastic and Aluminum， Copper， Steel.Ideal For DIY， Home and General Building/Engineering Using.Specification :Color : Gold(as picture shown)Material : High Speed SteelSurface : Nitrogen treatment (increasing the hardness and abrasion resistance)Shank:Triangle round handleScop : thin iron plate，aluminum，insulation panels，PVC panels 4mm thickness within the timber.Model:1/4~1-3/8"(1/4， 3/8， 1/2， 5/8， 3/4， 7/8， 1， 1-1/8， 1-1/4， 1-3/8")Shank Size:25 x 10mmTotal Height: 80mmPackage included :1 x 1/4~1-3/8" HSS Drill