Suitable for Trodat Professional rubber stamps: 5215 and 5415. The ink is water based and contains no toxic substances, no acid, no formaldehyde and no heavy metals. The ink is hygroscopic, meaning that it self regulates by absorbing the humidity of the surrounding air so that it does not dry out, allowing prolonged usage. The pads are available in black, blue, red, green and violet. Pads are also available as dual colour red and blue, which is suitable for the dater 5415 only. They are supplied a multiple pack of two.