The gasket's flap is compressed between the window frame and the trailer skin. For that reason, installation of this gasket requires removing the entire window frame from the trailer wall. The D-shape bulb is the cushion against which the front frame of the window closes. This creates a good water and air seal.
This gasket was used on the Hehr Standard windows used by Airstream (1952-58... and sometimes as late as 1960) and many other trailer manufacturers in the late 1940s through the early 1970s. It is also used on some utility doors on vintage trailers. It is a replica of original Hehr part number 009-101.
Because our gasket is made of silicone, it will not crack and shrink like the original.
Requires adhesive to apply. For adhesive, we recommend black or clear silicone RTV Adhesive. In general, silicone RTV makes an excellent adhesive for all our silicone rubber gaskets. Caution: do not allow excess adhesive to dry where you don't want it!