Works on: graphite from hard technical leads to soft charcoal

or any flat color block that needs to cover ground without showing brush strokes

The tricot nib handles different paint viscosities without clogging

synthetic nylon

pentel pocket brush pen refill cartridges 4 pack hiddenproduct Works on: graphite from hardFour replacement ink cartridges for the Pentel Pocket Brush Pen (GFKP GPP3 series). Push engagement seal swaps cleanly mid session with no leaks. Pigment based black ink waterproof and fade resistant once dry, so watercolor washes or alcohol markers can go over your lines without bleeding or reactivating. Contents: 4x black cartridges Ink: Pigment based, waterproof, UV fade resistant Fits: Pentel Pocket Brush Pen (GFKP GPP3)