Foam

No upholstery shop in the area. Tried hobby lobby and nothing. Lowe's, Menards, 2 different mom and pop hardware stores, zip.
I ended up going with something from McMaster Carr, $77 for 2, 12x12 squares, $10.some of that is shipping,.... Ridiculous for as little as foam weighs.... But got tired of going store to store and coming up empty. A lot of what McMaster showed said for sealing ac systems so I thought I'd even try asking at a local HVAC place, got the deer in the headlights response there too.