The Large ones. Needed one for a Silver A. The Part number I ordered was #99251. Everywhere I looked on the web said backordered and those I called told me that they have been waiting 8 months for Weber to send them. I called Weber direct and placed the order, she told me there may be a delay and got it in a week!
It was $37 shipped
Have to maybe assume they were waiting on larger mfg order from China and quite possibly have other models as well. Just putting it out there if people were looking for these things and having issues.