KWB Powerbox wood and Forstner drill set 5, 6, 15, 20, 25, 30, 35, 40 mm diameter 706078 (set of 8 pieces forged drill bits in accordance with ISO 7483 G) - - Amazon.com
Amazon.com: FAMAG 1663505 Forstner Drill Bit Set HM-Bormax3 5-Piece, Satz 5tlg. D=15,20,25,30,35mm : FAMAG: Industrial & Scientific
Steelex D3654 4-5/8-Inch Heavy Duty Forstner Bit with Screw Tip , black - - Amazon.com