2-cycle/4-cycle primer bulbs for handheld outdoor power equipment. 1 each of 3 different sizes to fit 2-cycle and 4-cycle Zama carburetors, Walbro carburetors that require .755 OD x .560 HT primer bulb, Echo, Homelite, McCulloch, Shindaiwa, Stihl, Troy-Bilt, Craftsman, John Deere, Ryobi, Bolens, Yard-Man, Ryan, Yard Machines, Husqvarna, Walbro that require .680 I.D. x .912 O.D., Green Machine, and Red Max.