Hero Arts Clear Stamps 6in x 8in – Kids United – Share projects all about Kids United with this Clear Photopolymer Stamp Set by Hero Arts. Included in the set are 14 clear photopolymer stamps that includes children hugging, hearts, and sentiments like “you are a true friend,” “my love goes out to you,” “together we can make a difference,” and more. The stamps can be used with acrylic block. your favourite inks, and the coordinating Kids United dies (each sold separately).