R Gauge - RE4000 - ELECTRODE SETTING GAUGE for RIELLO 40 F3, BF3, F5, BF5 and R35 OIL BURNERS. 5 mm above the center of the nozzle, 2.25 mm in front of the nozzle and a 4 mm gap between the electrode tips (The burner manufacturer instructions permit positioning the electrode tips from 2 mm to 2.5 mm in front of the nozzle) Sets the electrodes on the drawer assembly with or without the combustion head on /// P Gauge - PU5000 - ELECTRODE SETTING GAUGE for CARLIN 99CRD, 99FRD, 100CRD, 101CRD, 102CRD and EZ-66 OIL BURNERS. Sets the electrodes 1/4” above the center of the nozzle, 3/16” in front of the nozzle and a 1/8” gap between the electrode tips /// Y Gauge - YE6000 - ELECTRODE SETTING GAUGE for CARLIN EZ 1, 2, 3, LF and SELECT OIL BURNERS. Sets the electrodes 5/16” above the center of the nozzle, 1/32” in front of the nozzle and a 5/32” gap between the electrode tips /// Instructions included - Made in the USA