IRWIN 5-Piece Assorted Black Oxide Coated Hss Twist Drill Bit Set in the Twist Drill Bits department at Lowes.com
NEIKO 10218A Countersink Drill Bit Set for Wood and Metal, 1/4” Tri-Flat Shank, 5 Piece Countersink Bits, M2 High Speed Steel - Amazon.com
JNB PRO Countersink Drill BIT Set for Metal - 5 PC HIGH Speed Steel with 5% Cobalt HSS-Co M35 Grade, Sizes 1/4", 3/8", 1/2", 5/8" & 3/4" - 5 Flutes 82 Degree -
Snappy - Tapered Drill Countersink Bit Set - 3 Piece