A handy guide so you don't drill your holes all wonky. Comes with a neat little notch at the bottom for drilling into corners or cylinders.

Inch Sizes: 1/2, 7/16, 3/8, 5/16, 1/4, 3/16, 1/8

Metric Sizes: 10, 9, 8, 7, 6, 5, 4

Please hold firmly whilst drilling - I don't want anyone bashing their fingers because they spaced out & the bit jammed.