[Spade Drill Bit Sets]:It grabs the wood and carves it away,creating nice holes and reducing cracking [Paddle Flat Bit Sets]:The hex shank is 1/4,grooved to reduce slipping and prevent falling out,and is universally compatible most brands of drill tools on the market [Flat Wood Hole Cutter]:Drilling is sharper and faster,and chip evacuation is smoother.Precision drilling in soft metals such as wood,fiberglass,plastic,PVC (polyvinyl chloride),and aluminum [High Quality Material]:The wood drill bit set is made of high quality carbon steel,which is wear resistant and durable and can be used for a long time [Package Includes]:13Pieces impact drill bit set,size 1/4",5/16",3/8",1/2",9/16",5/8",3/4",7/8",1",1-1/8",1-1/4",1-3/8",1-1/2", Weight: 1.25883951602 pounds, Manufacturer: Zambuph