silicone,, not easy to break or corrode, and to use Easy to use, just put the stamp on the acrylic plate (not included), put the stamp on the card, then dry it to finish the exquisite work Suitable for both beginners and skilled people to great handicrafts at will Soft and flexible texture, good for home, making more delicate and beautiful Perfect for variety of decoration, such as diaries, albums, notebook, holiday cards, journals, scrapbooks, gift labels and other handicrafts items