3/16 in. Piloted Downward Spiral Saw Rotary Guidepoint Drywall Cut out Bits for Outlet/Window/Door Openings - China Spiral Saw Drywall Cutout Bit, Guide Point Drywall Cutout Zip Bits | Made-in-China.com
MAKITA 193452-3 Spiral Cut Out Bit,Guide Tip,10PK,1/8" - Walmart.com