If you strike out, RV Upgrades sells the type used on campers.
RV Slide-out Gaskets and Door Seals
I have bought other things from them with good success. They are based out of Ohio
As Jack said, McMaster Carr
McMaster-Carr
McMaster is an industrial supplier of just about anything. We use them at work and I had forgot about them for this. If you can find it on there, it may be cheaper then in the RV sector as the letters "RV" = more $$$
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Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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