The pad uses the larger rectangular ink surface, which is about 8cm x 5cm (3 x 1 3/4") in size. This is a fast drying ink (instant on paper and card, but can take a few minutes to fully dry on non-porous surfaces). The ink is also fully waterproof, so you can colour over a stamped image using water colours, blending pens or any other inks without smudging the original image. It is also acid free and archival quality. Permanent Ink, Azure, Great for metal, plastic, glass and other non-porous surfaces.