【8 Pcs Spade Drill Bit Set】Universal Size: Ø 6 / 10 / 13 / 16 / 19 / 22 / 25 / 32 mm. Total Length: 150 mm. The universal 1/4" hex shank fits most drills on the market. Sturdy and Durable: Our spade bit set is made of high-quality carbon steel construction. Thanks to the carbon steel material, the spade bit set has good wear resistance. After heat treatment of the whole body, the service life is extremely long. Hex Shank Design: The 1/4" hex shank allows for quick replacement. The 1/4" hex shank also prevents the drill from accidentally slipping. They can be easily and securely mounted on your drill. 【Unique Design】The unique three-pointed knife design helps quickly penetrate wood materials. Chips can be quickly removed with the grooved drill bit. Fast chip removal speeds up drilling and ensures smooth cutting.