This replacement pad is compatible with the MaxStamp M40 self-inking locking stamp. It features water-based ink which works great on documents, flyers, non-corrugated cardboard, envelopes and more. Make your impressions stand out with one of our 11 stunning ink color options. It can even be re-inked with water-based ink for extended use. Not recommended for glossy and non-porous surfaces. Select your ink color and then click the add to cart button!