These are premium quality soft lead pencils made by Staedtler of Germany. Designed for professional sketches and drawings, the Mars Lumograph pencils are especially break-resistant, easy to sharpen and easy to erase.
Staedtler Mars Lumograph pencils are available in 16 degrees. Below are a selection of tins: The tin of 6 includes 8B, 7B, 6B, 4B, 2B, HB; Tin of 12 includes the same plus 5B, 3B, B, F, H, 2H; Tin of 19 which includes every hardness, plus an extra 6B, 4B and 2B.
The individual pencils can be bought here.