This ink pad is suitable for the Trodat Printy 4916 and 4916 Typo rubber stamps. 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. They are packed in 2 pieces in a convenient blister.