Chartpak is a brand from the USA known by graffiti artists for their of AD Markers. These markers are used to do chisel-style handstyles in blackbooks and stickers due to their lasting ink and extremely versatile nib. Artists like Soem and Nurse have been known to use these markers in their artwork.
Handstyler stocks the Chartpak Tri-Nib AD Marker in Super Black. This is because the ink is very dark and is most likely the only one you'll want to use when flexing your handstyle.