Himm, 45295K54 is silicone for $70+
I like the Neoprene tubes better. I have used McMaster Neoprene to make Astrovent, heater box and kickpanel seals quite successfully. I think they are a better and cheaper option. Not sure what size would work best though (need to measure carefully).
https://www.mcmaster.com/neoprene-foam/multipurpose-blended-neoprene-foam-tubes/ Multipurpose Blended Neoprene Foam Tubes
Color: Black
Temperature Range: 0° to 165° F
Cell Type: Closed
For Use Outdoors: Yes
Density: 22 lbs./cu. ft.
Pressure to Compress 25%: 9 psi (Soft)
Tensile Strength Rating: Not Rated
Oil-Resistance Rating: Good
Neoprene is blended with EPDM and polyethylene for foam tubes that offer good resistance to water, sunlight, and oxidation. Use them as jackets, seals, and insulation. This foam has closed-cell construction, which restricts water, air, and gases from being absorbed. Tubes have an ultra-smooth texture for a sleek surface that's easy to wipe down.
3D CAD models availableFor technical drawings and 3-D models, click on a part number.
10 ft. Lg.
OD ID Wall
Thick. Each
1/2" 1/4" 1/8" 2029N11 $13.90
9/16" 3/8" 3/32" 2029N17 13.29
15/16" 5/8" 5/32" 2029N18 15.80
1" 1/2" 1/4" 2029N12 23.68
1" 3/4" 1/8" 2029N13 15.37
1 5/16" 7/8" 7/32" 2029N19 22.00
1 1/2" 3/4" 3/8" 2029N14 38.10
1 1/2" 1" 1/4" 2029N15 27.82
1 11/16" 1 1/8" 9/32" 2029N2 33.50
1 7/8" 1 1/4" 5/16" 2029N21 38.09
2 1/16" 1 3/8" 11/32" 2029N22 50.22
2 1/4" 1 1/2" 3/8" 2029N23 49.29
2 7/16" 1 5/8" 13/32" 2029N24 63.11
2 1/2" 2" 1/4" 2029N16 39.81