Several brands to choose from available in the drop down box.
All of these various markers have fibre tips so are more forgiving on rough surfaces, like rocks. They produce a 1mm line when new, as the tip wears and softens up especially on rough surfaces, you line width will increase slightly
Available as a set of 36 here or if you just need that 1 off replacement colour - we have several common colours here to choose from.
These acrylic paint markers are perfect if you are needing extra black and white markers.
Available in Black, White, Gold and Silver