These clear designer stamps are made of high quality photopolymer. They have a microscopically porous surface which gives superior ink transfer with all types of ink! Ready to use with any clear acrylic block (sold separately). MEASUREMENT REFERENCE: This set comes on a 3x2 acetate sheet. Hibiscus flower is apx 1.8" wide and 1.75 tall. The small leaf is apx 0.6 wide and 0.7 tall.