Upper panel: optical spectra of the Fermi BL Lac candidate BZB J0607+4739 listed in the Roma-BZCAT v4.1. Our observation clearly shows a featureless continuum and allows us to verify its classification. The average S/N is also indicated. Middle panel: normalized spectrum. Lower panel: 5′ × 5′ finding chart from the Digital Sky Survey (red filter). The source is indicated by the red circle.