These Copic Ink Olive G99 refills are an alcohol based ink that will not dissolve and works perfectly with mediums like watercolour and coloured pencils to create some striking designs. Markers like the Copic Sketch, Original and Ciao are completely refillable and compatible with this quick drying, permanent and non-toxic ink which has the benefit of being easy to clean up in case of accidents. To refill your marker simply dab the ink directly onto the nib with the help of the nozzle attached to the 12ml bottle, or alternatively you can use your Copic nib tweezers to remove the nib which will speed up the refills even more. Thanks to the bottles pen shape it makes it very compact and easy to transport and can fit in your Copic wallet when travelling. On the sides of these refill bottles are measuring guides so you can precisely and accurately top up whilst knowing exactly how much ink you have left. These recyclable 12ml refills of ink will be able to fill all of your markers around 5 to 8 times depending on the type of Copic marker you have, and once empty can be re-used to mix custom colours. Below are the range of Copic markers and how many times they can be refilled: Ciao: Approximately 1.4 ml or 9 times of refill Sketch: Approximately 1.8 ml or 7 times of refill Classic: Approximately 2.5 ml or 5 times of refill Wide: Approximately 3.4 ml or 3.5 times of refill - Brand: Copic - Made in Japan - Colour: Olive G99 - Capacity: 12ml - Measuring guides located on the bottle - Non-toxic, permanent and quick drying ink - Compact and portable design - Copic inks are paired perfectly with watercolours and coloured pencils - Once your bottle is empty you can re-use to mix custom colours