ONE PRIMER BULB WITH RETAINING RING. THEY REPLACE PART NUMBERS 694394, 494408, 49-058, 120-178, 5084, 8958, B1SB8958, 7-04947, 1709322, 1709322SM, BYNORM 320-306, HOME DEPOT 279640 AND NHC 262-4018. THE BULBS DO NOT HAVE A HOLE ON TOP. FITS QUANTUM SERIES 3.5 3.75 4.0 HP MODELS WITH RETAINER WITHOUT HOLE. NOT COMPATIBLE WITH GREATER THAN 10% ETHANOL FUEL