Crystal glue pen, 56-30033 Simplicity crystal glue pen includes 23 fluid ounces (7 ml) of glue for flat back crystals. Pen measures approximately 5 inches in length. For glueing flat back crystals. Crystals not Included. Apply glue to surface. Use tip to pick up crystals. Simplicity crystal glue pen includes 23 fluid ounces (7 ml) of glue for flat back crystals. Pen measures approximately 5 inches in length.