The Groen Z040809 Burner Jet #57 meters gas flow into the burner assembly of compatible commercial cooking equipment. The jet’s calibrated orifice controls the amount of fuel entering the burner, working with the available gas pressure and air supply to establish the intended combustion mixture. Its #57 designation identifies the specified orifice size for the applicable burner arrang... https://partsfe.com/burner-jet-57-for-groen-part-z040809