HIPA Pack of 5 188-12 Primer Bulb with 177-64 Check Valve for Most WT Series Carburetor Primer bulb replacement # 188-12 Check Valve replacment # 176-64 Primer bulb I.D. x O.D. x HT: 17/32" x 23/32" x 9/16" Package include: 5pcs primer bulb, 5pcs check valve