Eventually your ink pad will run dry, but that doesn't mean you need to buy a new one, simply buy this ink, apply to your stamp pad and it will as good as new. The 28ml bottle of blue ink is hygroscopic which means it absorbs the surrounding humidity allowing for prolonged use. The ink is manufactured with a water base and contains no toxic substances, no acid, no formaldehyde, and no heavy metals. Suitable for all re-ink able stamp pads.