The A19020 set has 15 different fractional sizes of the A100 drills in a plastic case. The A19020 set holds the drills in size order, clearly displaying the sizes so it is easier to select the diameter you need. The A100 drills in the A19018 set are made with a standard 118 degree point to provide strength. The point is also easy to regrind which makes the A100 a very cost-effective drill. Capable of being used for hand held drilling and machine drilling in many applications, the A100 has a steam oxide finish to reduce the chances of work piece material sticking to the cutting edge of the drill. A number of different materials can be drilled with the A100 including steels, aluminium and stainless steels. The drill diameter on ? inch and above is etched on the patented silver ring, which also helps you to know this is a genuine Dormer drill. The A19020 from Dormer is a good starter set of Dormer?s fractional drill sizes. *Note: all drills below 1mm are bright.