6PCS 4-Blade Saw Tooth Eccentric Drill Bit Hard Alloy Eccentric Twist Drill Bit High-Strength Four-Edge Eccentric Drill Bit 4/5/6/8/10/12mm Sawtooth Drilling Tools Professional Rotary Tool Accessory. Unique Four-Edge Eccentric Design: With a tilted four-edge eccentric drill bit design, positioning is more stable and penetration resistance is reduced.
eBay