Kerr Herculite XRV Ultra - Enamel - Shade A3.5 - 4g Syringe, 1-Pack. The Herculite XRV Ultra has been the industry standard for dental composites for 20 years. True to the Kerr legacy of developing innovative, quality products for dentistry, Kerr makes history again with the Herculite XRV Ultra nanohybrid composite.