These Bruynzeel graphite pencils are a high quality with a strong thick core to them. This set of pencils provides an excellent graphite transfer and a perfect balance of hardness. The core size ranges from 2.2 to 3.6 mm. The set of six includes one each of HB, 1B, 2B, 4B, 6B, 8B. This set also comes in a nice quality hinged tin for your storage convenience.