4mm 4mm Long Wood Drill, Extra Lange Bohrer, HSS Twist Drill Bits with Straight Shank for Hard Metal, Stainless Steel, Cast Iron and Other Hard Materials, 1 Piece - - Amazon.com
Famag 1594835 Twist Drill Bit Set 5 Pieces (Diameter 3-8, HSS-G, for All Wood Materials with Plastic Casette) Grey Set of 5 Diameter 3,4,5,6,8 mm - - Amazon.com
BGS Bohrer-Satz TLG 6801, HSS Drill bit Set, 10-11-12-13-15 mm, 5 Pieces - - Amazon.com