How can I order a the plastic bulb that you mash to charge the fuel on a feather lite plus poulan weed trimmer?

Most ACE hardware stores carry this item and they are cheap and easy to install.

Hi,
It has multiple part numbers. I saw them in my local Lowe's yesterday as a kit. They are all Walbro parts no matter what brand name appears on the package and all primers begin with 188-?? -1 as the part #.
Peace,
Clarke