Keo - Combo Drill & Countersink: 1/4, 1/4″ Body Dia, High Speed Steel - 31478258 - MSC Industrial Supply
NKTIER 29Pcs Countersink Drill Bit Set Heavy Duty Chamfer Drill Bit Multiple Size Step Drill Bit Wear Resistant Punching Drill Bit Woodworking Tool for Particleboard Fiberboard PVC Pipe - Walmart.com
Task T69004 Pilot/Countersink Drill Bit Combo, No.4 - Power Drill Accessories - Amazon.com