VERY good product, for what it sells, it comes with a large container at the back with 9ml (there is also another one with 4ml). 4 stars though because Pentel offers Aquawash (Pentel) for about half the price, and its cap doesn't look as cheap as Sakura's.

(EDIT) After 1 year and 7 months of rough handling!!! (heat, cold) BUT daily use.... I will say that it's better to get the equivalent from Pentel. Its mechanism made it stop being permanently wet, causing you to get tired because you had to constantly control the water flow. Its handle hardened and it tires you to press it and press it again. IF YOU CAN'T FIND IT BELOW the price they ask respectively.... look for something else. You don't pay for what you get.