These Pilot 30ml ink bottles are a great economical way to get into fountain pens. They are not so large as to require a long time commitment to a single bottle of ink (most inks come in 50ml bottles). The colors are staples for most uses, and a good foundation from which to compare other inks. Or, just use them all the time, as they are tried and true. Comes in 4 colors - black, blue, blue-black, and red. Black and blue-black are the most conservative and suitable for office work and general letter writing. Blue is a bit more flashy. Red is red!