A191 31M is a miniature drill bit set of 20 HSS drill bits from Dormer. Sizes supplied range from 0.3mm to 1mm in 0.05mm steps plus the following sizes 0.38, 0.52, 0.58, 0.78 and 0.82mm.

This miniature drill bit set is suitable for both professional and DIY enthusiasts to achieve precise and accurate results when in use.
Supplied in a plastic case which dispenses drills individually
HSS (high-speed steel) drill set No. 31M – HSS bits are hard and more resistance to heat than high-carbon steel
Bits increment in sizes of 0.05mm