Hero Arts-Clear Stamps. These clear stamps peel off their backing and stick to any acrylic block making for easy stamping. Simply apply your favorite ink and stamp crisp clear images! They are made from 100% photo-polymer which is latex free, phthalate free, non-toxic and biodegradable. This package contains Acts Of Kindness: a set of fifteen clear stamps on a 6x4 inch backing sheet. Made in USA.