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. The butterfly is apx 1.6" wide and 1.4 tall. you" is apx 0.5" wide and .0.16" tall