I had my full slide open metal grip rubber seal replaced with encapsulated rubber seal No. ZML-6705 (the metal gripper is sealed inside the rubber and not left open like the original seal) made by Clean Seal, Inc. (see Cleanseal.com). Research through the internet provided the answer for me for the open seal type construction problem. Plus the seal is a heavier rubber than the old spongy type.
Parkin Accessories provided the smaller amount of material which I needed - 50' minimum order of which 32' continuous length was used on my 21-22' slide.
Installation required removing the roller and laying it on the roof as well as removing the lift bars of the Carefree topper.
The original open metal grip rusted with the seal falling off twice in the first three years ownership from new rig purchase and even though sealed along the edges of the seal on the second installation.
The current encapsulated seal has been on since Dec., 2010.