HOOAI New UP04033 300780001 300780002 300780004 Snap in Primer Bulb Air Purge for Homelite Chainsaw (5pcs) Replace manufacturer part number: 188-512, 188-512-1 For Homelite UP04033 300780001 300780002 300780004 HOMELITE HLT28 ST145 ST155 CS50 CS4018 CS5020 D4150B D450B D4550BC CS40 We are professional auto parts seller! Please feel free to contact us if you are not sure which part to order! We provide 90 days warranty for all items from us!