Small glue stick forms a strong, long-lasting bond with just a single stroke. Glue goes on smoothly with no clumps. Washable, acid-free and photo-safe glue is ideal for paper, cardboard and photos. Patented threaded cap keeps air out, preventing dry-outs. Color stick goes on purple for precise application and dries clear. Glue is nontoxic and conforms to ASTM D-4236.