I've attached a pic of the seal used by Newell. The seal is made by Seal Masters and consists of two parts, the air seal (S-1) and the retainer. You can see in in the attachment how S-1 has a foot which snaps into the retainer. The retainer is glued to the coach body. I've been told that many times the air seal will fall out of the retainer groove. Newell applies an adhesive to this groove to help retain the seal. Don't ask how I know all this.
LOL! Seriously though, I need a second source air seal supplier for the slide in my LXi wanderlodge, so I've spent a great deal of time investigating what's being used by the various motorhome vendors including Newell. Hope this helps.
David Brady
'02 Blue Bird Wanderlodge LXi
NC