i would surmise they are off the shelf parts
try an OTR truck center,
there may even be a brand name or number on your bags, and they could source you a new one, firestone is just one of many that make them
ask your rv dealer to get the part number and see if it crosses to another vendor
USN Retired, Life time member of the DAV.
Enjoying the 2008 Damon Tuscany 4056, #3998 no your eyes are fine, there are really 6 slides
2022 F150 King Ranch or 2012 Edge toads