Various Ink refills are part of what make the Copic system truly amazing. All 358 marker colors have a matching bottle of ink. Each bottle will fill a dry marker up to 15 times, depending on the style of marker. Measuring guides are built into the bottle, assuring easy and precise refilling. Each bottle of ink has a built in dropper tip for simple application. If needed, an additional Booster Needle can be attached for even more precision. The airtight inner seal will prevent the ink from drying out for many years. Various Inks are non-toxic and easy to cleanup.