Line width approx 1.5 to 3mm. Low-odour Indian ink, without butyl acetate added, which can be dry wiped from virtually all non-porous surfaces such as enamel, glass or melamine. The 'cap-off' ink allows the board markers to continue to write effectively even if the cap has been left off for a few days. Refillable board markers with aluminium barrel and exchangeable round tip.