flexible rubber boot

can somebody tell me where to purchase a flexible rubber boot that goes between the cab and the camper(to be) part of my rv?

[KAYE RIVERCITY]

.....check with a compamy that makes tents and awnings...last one I saw was made here in Cincinnati it was white plastic canvas on the outside-with a layer of insulation[re-bonded carpet padding]-then a layer of dark brown leather looking vinal on the inside with a round vinal bead on both inside and truck side of the boot.....there was a aluminum channel which was bent around the inside and truck side opening which the boot slid into with a zipper at the bottom on both sides so the boot could be installed.....the cost IIRC was $50....geof