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 6x4 acetate sheet. Big flower solid base is apx 1.5" wide and 1.25 tall. The set of 3 tiny flowers in left bottom apx 1 wide and 0.60 tall.