Derwent XL Graphite Sticks
Everything about Derwent XL Graphite is big; big blocks and even bigger possibilities. You can create a wide variety of textures and effects with these generous graphite blocks; subtle blending, fine lines and deep tonal work are all possible.
They have developed 6 dense shades from Olive Green to Burnt and Raw Umber which work really well for bold landscape drawings.
Have a look at this video for some ideas on using water soluble graphite
Here is a video showing the Derwent groove Cube
Here is a video showing the Derwent Sprinkler
Here is a video showing the Derwent XL gripper