Fits Trodat Printy rubber stamp 4630. 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 dry felt which are suitable for special inks. They are supplied a multiple pack of two.