"GP" Graphites Grade Grain Size Inches Density g/cm Compresion PSI Flex PSI Hardness Shore GP-1 0.0015 1.70 10,000 5,300 48 GP-10 0.001 1.75 14,285 8,571 50 GP-5 0.001 1.75 14,285 9,285 55 GP-3 0.0005 1.80 15,714 8,571 65 GP-3c Copper Impregnated         GP-6 0.0005 1.80 20,443 11,654 62 GP-7 0.0005 1.85 20,000 10,000 70 GP-4 0.0002 1.90 25,714 14,285 75 GP-25 Extruded Graphite 1.75   3,553   GP-200 Extruded Fine Grain- Baked Carbon Rods 1.68   4,500   GP-500 Extruded Fine Grain- Graphite Rods 1.72   4,200