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 4 x4 acetate sheet. The top left stamp is apx 1.45 wide and 1.3 tall. The leaf in the left bottom is apx 0.65 wide and 0.55 tall.