Help finding a rubber diaphragm for a water tool

[marshak]

I have a few watering tools that need this rubber diaphragm. The company no longer makes the part. It has a diameter of about 22mm and a thickness of around 5.5mm.

Does anyone know a supplier that may carry something like this. The pic is of the front and back of the diaphragm

Thank you

 

[The Cobbler]

imagine it seals the water off ? does it need to be profiled like that or would a soft rubber disc work ? maybe with a dimple recessed in the center?

 

[marshak]

It seals the water off when the plastic shutoff it moved

 

[jonesg]

auto parts store sells dorrman firewall blanking plugs and seals.
Also, the seal that sits on brake fluid reservoirs look like that, I dunno if they're vented.