Noodler's Ink Waterase Blue 4.5oz. is a nice blue and comes enclosed with a free Pen.
Properties of the ink:
Use a slightly wet cloth to erase. Also suitable to use on regular paper as a standard conventional fountain pen ink. All Noodler's inks are hand made in small batches and the colours can vary slightly from one bottle to another.
Be Careful while opening as the bottles come full to the brim.