Flat again...but after a day or so, but the other wheels remian as inflated as they were a month ago, clearly still a leak.

Before I pull the oring out again, I am wodnering if I can find a replacement in case it breaks or doesnt seal this time.

Does anyone know where I could find that exact Oring? I have not seen one quite like it at the local hardware stores.. I would like to have a few backups if possible.

Thanks
Dave